// OVE — app identity + version stamp.
//
// Single source of truth for the product name and version shown in the UI
// (header, footer, document title). Bump APP_VERSION whenever we ship a
// large change so the running build can always be identified at a glance —
// useful both for the z.ai Version History and for naming local backups
// (v6.0 = rename to Open Visualization Engine + version indicator).
//
// STANDING RULE (since v7.6): every APP_VERSION bump MUST come with a
// matching entry at the top of RELEASE_NOTES in src/lib/release-notes.ts —
// that list powers the header's "What's New!" dialog. A dev-mode guard
// warns in the console when the two drift apart.
//
// History:
//   7.19 — Automatic true-black (user request, "Texe-rings"): the v7.17
//           trueblack tail is no longer opt-in. Root cause of the smear
//           the user saw: the persistence fade multiplies the framebuffer
//           by persist in 8-bit steps, and round-to-nearest leaves fixed
//           points -- at persist 0.78 every premultiplied value 1..2
//           satisfies round(v*0.78) == v, so ring trails settle into a
//           faint permanently-stuck wash (colored, not gray, because the
//           script's channels divide by different constants and each
//           channel sticks at its own quantum). No multiply-only
//           compositing can fix that (proven: unsticking v=1 needs a
//           multiplier < 0.5, which halves the trail every frame), so the
//           fix is a subtractive -1/255/frame tail -- and the reason it
//           could become automatic is a NEW implementation: shader mode 22
//           in the WebGL compositor (blend-gpu.ts) clamps
//           max(premult-1/255, 0) on rgb AND alpha in one pass. That is
//           exact in 8-bit (black stays a true 0, unlike the Canvas2D
//           'difference' fill's 0<->1 flicker) and alpha-PRESERVING, so
//           behind/clear art keeps its holes (which now heal to truly
//           empty too -- stuck alpha quanta sweep like everything else).
//           Engine policy: the sweep runs by default exactly in the
//           sticky zone (persist >= 0.5), so low-persist scripts pay
//           nothing and nothing visual changes where the multiply already
//           decayed fully. The old 'difference' fill survives only as the
//           no-WebGL fallback, and it stands down once a script has drawn
//           with behind/clear (the alphaArt latch -- pre-latched from the
//           header blend, latched at draw time on a per-frame env.blend
//           switch). The trueblack: header becomes a tri-state: auto
//           (default, the new behavior), on (forced at any persist < 1,
//           the v7.17 flag), off (never -- the wash look, for authors who
//           want it). Texe-rings itself needs no edit: at 0.78 the auto
//           sweep clears each channel's quanta in 2-3 frames after the
//           multiply stalls, and the background returns to pure black.
//   7.18 — "Beautiful Spectrogram" (user request, twelfth Zai-Magic
//           preset): a true scrolling spectrogram as a pure script -- the
//           v7.12 bgx feedback slide moves the whole framebuffer left
//           every frame (the time axis) while persist 1 (v7.14.1's
//           zero-fade framebuffer) keeps the history locked, so the print
//           only ever leaves by scrolling off the left edge. The write
//           head is a 256-point vertical line at the right edge: sv (the
//           per-point spectrum) drives a megabuf attack/slow-decay level
//           per frequency bin, which indexes a six-anchor palette table
//           (also megabuf) -- deep dark blue background, then pink -> red
//           -> orange -> yellow -> white as bins get loud. Two tricks make
//           it read clean: (1) the stroke is exactly four scroll-steps
//           wide with its per-frame alpha pre-divided by the accumulation
//           factor (core 0.9 + halo 0.22*3.2 passes, times four overlapping
//           steps ~= 1.6*4), so overlapping columns sum to exactly full
//           palette strength and the quiet field renders as SOLID navy
//           rather than banded; (2) a half-second erase phase (per-frame
//           persist override to 0.45) drains the previous preset's
//           framebuffer before the zero-fade lock engages, and a 15x
//           three-second fill sweep (plus a replay on stage resize) paints
//           the navy field across the whole screen instead of making the
//           visitor wait 25 s for the crawl to cover it.
//   7.17 — True-black trail fade (user request, "Orange Burst"): the
//           persistence fade multiplies the framebuffer by persist in
//           8-bit steps, so any persist >= 0.5 leaves fixed points
//           (round(v*p) == v -- at 0.88 every value 1..4 is stuck) and long
//           trails settle into a gray wash that a bg* blow-out then smears
//           into every corner; scripts were forced below 0.5, where the
//           trail dies in ~5 frames and the blow-out echo becomes
//           unreadable. New opt-in header trueblack: on adds a subtractive
//           tail right after the alpha erase: one fullscreen 'difference'
//           fill of rgb(1,1,1) = an exact -1/255 per pixel per frame, which
//           sweeps the stuck quantum values to a true 0 while bright
//           pixels never notice (a 0.93 multiply halves them every ~9
//           frames anyway). Costs one extra fullscreen fill, only when the
//           flag is on; runs inside the persist < 1 branch so persist 1
//           keeps its zero-fade (permanent) semantics. The tail forces
//           pixels opaque (alpha composites to 1 under 'difference'), so it
//           must never be combined with 'behind'/'clear' art -- documented
//           in the Help panel's file-format section, off by default. Also:
//           the script parser's unknown-header error now lists all nine
//           valid keys (ysign had gone missing from the list).
//   7.16 — Presets tab rearranged (user request): "instead of having the
//           two sections side by side ... the 'Load Preset' button section
//           is on top with full width use of the preset section, the height
//           set to where there is no empty space being wasted (even when a
//           preset is selected). The preset tree should be placed below
//           that with its width expanded to use the whole width of the
//           Presets section ... so the preset names won't be clipped due to
//           a restriction of horizontal space." The old 58/42 side-by-side
//           split is gone: the management panel (selection header, action
//           buttons, club-mode randomizer) sits ON TOP at the section's
//           full width and its natural height -- never stretched, so the
//           dead space that used to sit under the buttons when a preset was
//           selected is gone. Its buttons pack into one compact grid row on
//           desktop (Load Preset | Rename | Delete for an own preset with
//           the primary Load cell wider; Load | Copy to my presets for an
//           embedded one; a 2x3 grid -- Create | Subfolder | Rename over
//           Delete | Export | Import -- for a user folder), all cells one
//           uniform h-9; phones keep the previous stacking (primary action
//           full-width, pairs below). The tree follows BELOW at full width
//           and fills every bit of height the tab has left (the tab body's
//           h-full flex chain; capped at 420 px only below lg, where the
//           page itself scrolls and the cap keeps nested scrolling sane) --
//           full-width rows mean preset names never clip against the old
//           58% column's horizontal squeeze. The club-mode scope line and
//           the active RANDOM/SEQUENCE pill now share one row (truncate +
//           shrink-0) instead of stacking.
//   7.15.2 — Facebook page + theme switch relocation (user request): the
//           project now has its own Facebook page, and the footer's
//           right-hand group carries the link (facebook.com/openvisengine)
//           beside the version stamp -- an icon-only button (lucide
//           Facebook glyph) that opens in a new tab, same hover/focus
//           treatment as the portfolio link. The light/dark tick switch
//           (v6.3) moved out of the header into the Settings tab's
//           Appearance section, as a "Light / dark mode" row ABOVE the
//           base-theme cards -- the header is one control lighter and all
//           appearance controls now live in one place. Mechanics are
//           identical: checking = the white theme, unchecking returns to
//           the visitor's stored dark base (kept fresh by the base cards),
//           both choices persist per visitor, and the mount guard keeps
//           the SSR render mismatch-free. The row states the current side
//           ("Light theme" / "Dark theme") and explains the return-to-base
//           behavior in its caption.
//   7.15.1 — the silence hold (user request): "if silence is detected,
//           it needs to place an immediate override and hold on the beat
//           detection / prediction ... if silence is no longer detected,
//           release the hold ... (the waveforms effects should still come
//           through but if there is no beat, the visual should stop acting
//           like there is a beat)." Sustained near-digital quiet on the
//           OVERALL level (< 0.006 for 300 ms — the 3-band mean the engine
//           already computes; digital silence reads exactly 0, mastered
//           music stays above ~0.05 even between hits) now places a HOLD:
//           nothing fires — real or predicted — the tempo estimate and
//           confidence freeze exactly where they are (the old path let the
//           predictor fake beats for up to ~2 s into a silence while its
//           confidence quietly eroded), and beatphase freezes for scripts
//           instead of saturating at "beat imminent". The hold is STICKY
//           (only a decisive level above 0.015 releases — noise-floor
//           wobble never does) and the release is immediate, re-anchoring
//           the grid from the phase captured the frame the audio went QUIET
//           (before the debounce window, so a pause/resume keeps perfect
//           time — the music continues from the exact position it stopped
//           at); after a hard cut the comb + first real beats re-align
//           within a couple of periods. The 300 ms debounce only has to
//           beat the ~800 ms the old flux-domain path needed before it
//           started faking beats
//           (bassGone = 1.6 periods at 120 BPM), so inter-attack dips in
//           sparse masters never trip it. "Set Beat" taps release the hold
//           outright — the manual override. Band/waveform data is NOT
//           gated: it still flows (and is simply ~0, because the audio is
//           gone). Scripts get a silent variable (1 while held) and the
//           beat indicator shows an amber HOLD badge while it is active.
//           BeatFrame.silent carries the state; rust-agent/src/beat.rs
//           ports the same gate (its bass level doubles as the silence
//           signal) with the same thresholds.
//   7.15 — the complete blend mode collection (user request): the blend
//           header grew from six keywords to a 41-mode registry
//           (src/lib/ava/blend.ts) covering every compositing family in the
//           request list -- the full Photoshop set, the GIMP grain pair,
//           the After Effects stencil/silhouette masks, Apple/CSS plus-
//           lighter/plus-darker and the Pegtop exotica (negation, phoenix,
//           reflect, glow). Native keywords map straight to Canvas2D
//           operators; the 21 modes Canvas2D lacks run through a new WebGL
//           compositor (blend-gpu.ts) with per-pixel formulas from the W3C
//           compositing spec, the glsl-blend collection and GIMP (phoenix =
//           min - max + 1, verified against four independent sources; hard
//           mix = vivid light thresholded at 0.5). 'subtract' is now a TRUE
//           clamped subtract, replacing 7.14.1's difference approximation.
//           The framebuffer went alpha-capable so behind and clear work
//           honestly: the persistence fade is an alpha ERASE
//           (destination-out) and the bg* wipe a clearRect -- over the
//           black stage both read pixel-identically to the old opaque
//           fills, so every existing preset renders as before. The blend
//           variable can switch the mode per frame (same contract as
//           persist; it carries the mode's 1-based registry number because
//           the expression language is numeric-only -- the Help table lists
//           every number). Names are case/separator-insensitive
//           with aliases (color burn = colorburn = ColorBurn; plus-lighter
//           = additive; plus-darker = linear burn). Help panel gained a
//           grouped 41-row Blend modes table; parser errors point at it.
//           WebGL-less browsers fall back to the nearest native operator
//           per mode.
//   7.14.1 — Script engine: blend modes + zero-fade persistence (user
//           request, Brainstorm preset session). The renderer's content
//           pass could only composite additively ('lighter') or plain
//           alpha; the persistence header was hard-capped at 0.98, so a
//           feedback blow-out ALWAYS faded -- the user wanted colors that
//           ride outward forever at full brightness, replaced at the center
//           by new color. Blend header extended to six values: multiply,
//           screen, subtract (canvas 'difference' |dst-src| -- Canvas2D has
//           no clamped true-subtract op; difference is the classic
//           approximation and can never climb to white) and replace
//           (source-over with the CORE pass at FULL alpha -- fresh strokes
//           overwrite the pixels under them instead of stacking, so a
//           figure redrawn over its own accumulating trails keeps its color
//           instead of saturating to white; halo pass 0.25, dots core
//           alpha 1.0, solid fill alpha 1.0). persist header + env override
//           widened 0..0.98 -> 0..1; at exactly 1 the fade fill is SKIPPED
//           entirely (engine.ts). The pairing this was asked for: blend
//           replace + persist 1 + the v7.12 bgzoom/bgrot feedback = a
//           static-speed blow-out that never fades, the fresh drawing
//           replacing the old color at the center -- the blow-out itself is
//           the cleanup. Help panel + parser error strings updated; no
//           library changes (existing presets keep additive/alpha and their
//           behavior byte-for-byte).
//   7.14 — Arctic Rainbow re-imagined (user request): the old stand-in was
//           plain white columns of rain dots sweeping upward. Rebuilt as a
//           music-driven water spray, stateless projectile physics in the
//           [point] program: each of up to 120 droplets is a deterministic
//           parabola (own apex height 1.26..1.88, own flight time 1.9..3.4 s,
//           phase-staggered clock; every splash cycle re-rolls its origin,
//           drift and arch) -- launch from below the bottom edge, slow rise,
//           hang, arch left or right, fall back off-screen. Drop count
//           follows the music (vol_att/bass_att envelope, fast attack 6/s,
//           slow release 1.2/s: silence = 0 drops, loud = all 120). Each
//           drop owns a hue that shifts by its own per-drop amount on every
//           detected beat, plus a subtle gradient along its tail. The tail
//           is 12 explicit trail samples (0.014..0.44 s back along the arc)
//           drawn as a tapered polyline in lines mode, gated by smoothstep
//           on the fall speed: nothing while rising (crisp dot), fading in
//           as the arch turns downward -- no persistence smear (persist
//           0.12). Slot map through cell centers (the v7.13.1 lesson), 14
//           slots per drop (separator + head + 12 trail), n = 1680.
//           EMBEDDED_SEED_VERSION 7.13.1 -> 7.14 re-seeds the library.
//   7.13.1 — Beat Matrix endpoint fix (user report): the rightmost column
//           of dots sat one row short -- its bottom dot missing -- while a
//           phantom dot spilled one column past the wall's right edge at
//           the top. Root cause: the engine's point position i spans 0..1
//           INCLUSIVE (classic AVS Superscope convention, engine.ts: i =
//           k/(n-1)), but Beat Matrix's grid math assumed exclusive i = k/n:
//           floor(i*cols) turned the last point into col 16 (one past the
//           16-column wall) at row 0, and column 15 was left with nine
//           dots (rows 0-8, no bottom). Fix: the script now maps through
//           cell centers -- cell = i*(cols*rows-1)+0.5, col =
//           floor(cell/rows), row = floor(cell-col*rows) -- which puts
//           every floor() half a cell away from an integer boundary, so
//           the endpoint can never spill and float dust can never shuffle
//           a dot. Full 16x10 bijection verified headlessly (all 160
//           points in 160 distinct cells, col<=15, row<=9, bottom-right
//           cell present). Sweep of the other 100 presets: every other
//           floor(i*M) use is benign -- angular presets close their loop
//           (bar=bars lands exactly on bar 0's angle), Aurora Veil's
//           phantom lands off-screen (x=1.19), the megabuf particle
//           presets draw their phantom slot at alpha 0, and the converted
//           Winamp classics rendered identically under original AVS
//           (which also uses inclusive i). EMBEDDED_SEED_VERSION 7.12 ->
//           7.13.1 re-seeds the library so every visitor gets the fixed
//           Beat Matrix.
//   7.13 — one build, every feature: the parallel development lines are
//           merged. This tree now carries BOTH the community OVE-Directory
//           (v7.11 here) AND the parallel line's additions — the spectrum
//           16 kHz cap (its 7.10.1), the screen wake lock + respectful
//           Demo button + one-click Save (its 7.11, folded into this
//           history as 7.10.2 to keep one clean timeline), and the
//           AVS-style background movement family (bgrot / bgx / bgy /
//           bgzoom) with the eleventh Zai-Magic preset "osc-rotations"
//           (its 7.12). Git three-way merge against the shared v7.10
//           ancestor (identical tree hashes verified on both sides); the
//           only hand-merged surface was the Script tab toolbar, which
//           now carries the one-click Save and "Upload to OVE-Directory"
//           side by side, and the two changelogs (here + release-notes).
//   7.12 — background movement + osc-rotations. Scripts can now move the
//           whole framebuffer every frame, the way the classic Winamp AVS
//           plugins did: bgrot (radians/frame, + clockwise on screen),
//           bgx / bgy (per-frame drift in the -1..1 screen convention, y
//           up), bgzoom (< 1 draw-in, > 1 blow-out) -- read after [frame]/
//           [beat] so this frame's values apply this frame. The engine
//           snapshots the canvas into an offscreen buffer, wipes, and
//           draws the snapshot back through the transform, so the
//           persistence fade blends the moving trails: "speed accelerates
//           to the beat, a hard hit flips the spin, fade to black stays
//           slow" is pure script (a beatage envelope drives the rate; a
//           [beat] section flips a dir variable on hard hits via bass vs
//           bass_att). Neutral readings (0/0/0/1) skip the pass entirely
//           (zero cost for every preset that doesn't move); non-finite
//           values fall back to neutral (a NaN in a canvas transform
//           matrix would black the screen with no error); per-frame
//           clamps: rot ±0.6 rad, drift ±0.25, zoom 0.5..2. New 11th
//           Zai-Magic preset "osc-rotations" (user-requested): a
//           stationary centered oscilloscope (time-domain v) whose color
//           is mirror-symmetric -- points equidistant left/right of
//           center shift together, the center points hold their own hue
//           -- over a background rotating cw/ccw to the music that
//           temporarily accelerates on the beat; hard hits
//           (bass > 1.25 × bass_att) flip the spin; a whisper of draw-in
//           (bgzoom ~0.999) spirals the trails inward; persist 0.965
//           keeps the fade slow so colors blend. Help panel: bg* variable
//           rows + three new example formulas. EMBEDDED_SEED_VERSION
//           7.10 -> 7.12 (library re-seed adds the preset; the share
//           codec's dictionary stays frozen per its compatibility
//           contract -- bg* identifiers ride the pair packing like any
//           custom variable). Headless validation of the preset's
//           compiled programs: quiet 0.004 rad/frame, hard beat 0.026
//           (6.5×) + direction flip, soft beat no flip, mirrored points
//           share hue / center distinct
//   7.11 — the community OVE-Directory. A sixth tab (Directory) lists every
//           script published to the community directory — a separate VPS at
//           s3374dir.openvisengine.com, reached ONLY through this server's
//           backend proxy (/api/ove-directory/*), which holds the API key in
//           env and re-validates every upload (the share string must decode
//           AND compile). Publishing: the Script tab gains "Upload to
//           OVE-Directory" (enabled only while the editor shows ✔ Compiled OK
//           with no runtime error); the script travels as its Script⇢Hash
//           string, so the directory stores a fraction of the source. The
//           listing carries each entry's name, type and date, a 1–5 star
//           widget (the voter id is an HttpOnly cookie minted by the proxy;
//           one vote per script per visitor, enforced upstream), the live
//           "Average: #.#" to the right of the stars, and sorting by Name /
//           Type / Date / Rating (done upstream, both directions). "Get"
//           fetches the full record, decodes the hash back into the exact
//           script, files it in this browser's preset tree under
//           root/user created/OVE-Directory (content-deduped, names numbered
//           "(1) (2) (3)…" on collision) and offers "Open in editor".
//           Duplicate uploads resolve as success (409 DUPLICATE_HASH carries
//           the existing row); duplicate votes show the stored aggregates.
//   7.10.2 — wake lock, a respectful Demo button, one-click save. While any
//           audio source is live the site holds a Screen Wake Lock so phone
//           and tablet screens stay on (released the moment the engine goes
//           idle so the normal inactivity dimming returns; browsers silently
//           drop the sentinel on hide, so a visibilitychange watcher
//           re-acquires it on return while music is still going;
//           unsupported browsers degrade silently). The Demo Track button no
//           longer force-engages the Sequence checkbox: a visitor who loaded
//           a preset (tree double-click / Load / Copy to my presets / created
//           one), brought their own script material into the editor (typed,
//           pasted, Hash⇢Script, file), saved their own default startup
//           script, or runs their own Random/Sequence mix keeps their
//           selection -- Demo just plays the track (the showcase's tree
//           re-scope, 20 s interval and retire-on-end all skip too; a new
//           per-visit manualChoice flag + a boot-script snapshot decide, and
//           ensureDefaultPreset gained the same guard so mic/file/link never
//           clobber a custom draft either; the showcase now only starts for
//           a visit that never picked or typed anything). Script tab: a valid
//           script shows the Save button with NO save target needed -- one
//           click creates a preset under "user created", auto-named from the
//           script's name: header (a hash import of "Spectrum Bars:[▼…]"
//           saves as "Spectrum Bars"), "Empty Name" when nameless, " (1)"/
//           " (2)"… suffixes on conflicts, and whenever the name had to be
//           invented a "Give This Preset a Name" dialog opens to rename the
//           just-saved preset in one step (the preset is always saved FIRST,
//           renamed second, so nothing is ever lost to a naming problem).
//           Hash⇢Script imports clear the stale save target (the editor now
//           holds foreign content) and pass the decoded label through as the
//           save-name fallback when the script has no name: header
//   7.10.1 — the frozen right edge of spectrum visuals. getspec()/sv mapped
//           the bar field across the whole FFT (bin 2 ... Nyquist, ~12 Hz to
//           24 kHz), but music carries almost nothing above ~16 kHz and every
//           lossy source low-passes even lower (192 kbps MP3 at ~18.6 kHz,
//           YouTube AAC at ~15.5 kHz; measured across the demo collection:
//           0.000% of total magnitude above 18.6 kHz), so the rightmost ~20%
//           of every spectrum visual read a permanent zero -- bars that never
//           moved. getSpectrum() now tops the field out at 16 kHz
//           (SPEC_TOP_HZ, matching the spectral-flux cap in getBands()), so
//           the right edge lands on the 12-16 kHz "air" band where cymbals,
//           hats and synth sparkle live. rust-agent's spectrum_at() mirrors
//           the change, and the help panel's sv entry now states the span.
//   7.10 — ten demo tracks + first-person changelog + declutter. The demo
//           source is now a COLLECTION: ten mastered tracks in
//           public/demo-tracks/ (demo-01.mp3 … demo-10.mp3, filename order
//           1→10, replacing the single Neural Mecha Pulse file). Each Demo
//           click plays the visitor's PLACE in the collection once through;
//           the place advances when a pass truly ends — natural finish or
//           the Stop button ('ended'/'stop' teardown reasons, a new
//           onDemoEnded signature) — and wraps 10→1; switching to another
//           source keeps the place. The place persists per visitor in
//           localStorage (ove.demoTrack.next), so returning picks up where
//           they left off. The engine caches one decoded buffer at a time,
//           keyed by track index (~50–60 MB PCM each — all ten would be half
//           a gigabyte). The header chip + footer SRC label show the current
//           track's name (Demo Track N). RELEASE_NOTES rewritten in the
//           operator's first-person voice (no more third-person marketing
//           copy or addressing the visitor), and every em dash in the
//           interface replaced with a plain double minus ( -- ) — including
//           the embedded preset library's descriptions and script comments
//           (EMBEDDED_SEED_VERSION 7.01 → 7.10 re-seed). Declutter: the
//           landing menu's source list line, the presets panel's two
//           read-only paragraphs, the Random/Sequence hint line, the empty
//           user-folder note reworded, the Settings theme/highlight/Native
//           paragraphs, the link dialog's privacy footnote and the footer's
//           engine-ok dot are all gone — compile errors still toast, so the
//           always-green badge was noise
//   7.9 — footer credit + What's New polish. The footer's blank middle now
//           carries the maker's signature: "© {year} · Site Created &
//           Deployed by Sum'ting White" (year generated from the clock,
//           hydration-guarded) with a "View my portfolio at zcreations.dev"
//           link that opens zcreations.dev in a new tab — centered in the
//           blank area from xl (mx-auto between the stats and the version
//           stamp), dropping to its own centered row on narrower screens so
//           nothing ever crowds. The What's New dialog got a typographic
//           tidy-up: a hairline divider above every release box
//           (border-zinc-800 — a ramp step, so it matches every base theme
//           through the globals.css remaps), and each change row became an
//           invisible two-column grid — the kind tag top-right justified
//           against the column boundary, the description top-left with word
//           wrap — so all descriptions start on the same pixel column
//   7.8 — share strings 2.0: ~72% shorter than the script (was ~49%). The
//           base-62 idea, cranked to 11,172… 32,164: after the symbol
//           dictionary (which grew ~170 data-mined entries — every function
//           WITH its open paren, every engine variable, the AVS idioms
//           "hue = hue + dt * " and "t = t + dt * ", " * 0.", ") * ",
//           blank-line+section skeletons, "linewidth: " / "blend: additive"
//           headers, ~70 number literals, and the library's common
//           variable names incl. chroma) the whole body is read as ONE BIG
//           NUMBER and rewritten in base 32,164 — one digit per character
//           from the CJK + Hangul blocks, ~15 bits a character vs base-62's
//           5.95 (so "1400" costs ~0.85 of a character). The decoder gets
//           the body's alphabet back from a ~32-character bitmap header
//           instead of ~80 literal symbols. Short scripts where the header
//           wouldn't pay keep the v7.7 symbol form (encoder picks whichever
//           is shorter); ▲ strings from v7.7 still decode; still lossless
//           for ANY text, still copy-safe, still self-checking. Corpus
//           measure: median share string is 27% of the script's length
//           (best 22%), e.g. Bass Bloom 1341 → 326 characters
//   7.7 — script sharing + settings declutter. Script⇢Hash / Hash⇢Script:
//           two buttons in the Script tab turn the editor's script into ONE
//           short shareable Unicode string ("Bass Bloom:[▲…①①①①①①①①]") and
//           paste one back — the script returns exactly as written (lossless
//           for ANY text, compiling NOT required, so WIP scripts can be
//           shared for debugging). The string is built from built-in symbol
//           references (♤ = line return, ♡ = beats, ♠ = beatage, ♦ = space,
//           ♩♪♫♬ = the four sections, one symbol per function/variable, plus
//           a pair-packing layer that folds leftover identifier/number text
//           two chars per CJK code point) — ~50% shorter than the script on
//           real presets. Copy-safe by construction (no raw whitespace or
//           control chars; platform-injected variation selectors / zero-
//           widths stripped on paste) and self-checking: 8 check digits (an
//           FNV-1a digest rendered as ①–⑯) reject strings that were cut off
//           by a character limit or altered in transit, instead of decoding
//           into garbage. Also: the Music Services log in / "log out of all"
//           section in Settings is parked (MUSIC_SERVICES_UI flag) — the
//           built-in house account already powers Stream-a-Link for
//           everyone; the section returns reworked in a later update
//   7.6.1 — header declutter: the Set Beat button is gone from the header
//           (tap-tempo lives in the Beat tab, and the Space shortcut works
//           anywhere — both unchanged). The beat indicator dot stays.
//   7.6 — "What's New!" dialog: a Sparkles button in the header (left of
//           the theme switch) opens the visitor-facing changelog — every
//           release from v4.0 on, newest first, each with one-line Added /
//           Improved / Fixed / Removed notes (src/lib/release-notes.ts,
//           color-coded tags, the running version badged "current",
//           scrollable with the thin scrollbar). A small emerald dot on the
//           button marks updates the visitor hasn't seen yet — per visitor
//           in localStorage, cleared on open (mount-guarded, no hydration
//           mismatch). Standing rule added: version bumps ship with their
//           release note; a dev-mode guard warns when they drift
//   7.5.1 — Link dialog width fix: text no longer escapes the dialog box.
//           Root cause: Radix dialogs lay their children in an implicit CSS
//           grid whose single column sizes to the widest child's min-content;
//           the RECENT LINKS rows carry truncate spans (white-space: nowrap),
//           and Chromium measures a nowrap flex item's full text width for
//           that measurement — so a long saved title (e.g. "Bobby Foxx — This
//           Is Why We Can't Have Nice Things (Official Music Video)") blew
//           the column ~40 px past the 448 px dialog, and EVERY child (title,
//           description, input + Load, rows, footer) laid out beyond the
//           right border. Fix: the shared Dialog/AlertDialog content now pins
//           the column to minmax(0,1fr) — capped at the available width, so
//           no nowrap content can ever stretch a dialog again (covers every
//           dialog app-wide) — the Link dialog widened to max-w-lg for
//           comfier wrapping, and min-w-0 + break-words added on the
//           recents/playlist containers and error text as belt-and-braces
//   7.5 — yt-dlp compatibility: single tracks resolve by DOWNLOAD + CONVERT
//           instead of proxying the extractor's stream URL. The old stream
//           URLs were IP-locked (googlevideo bakes in the resolver's IP),
//           expired within hours, and arrived as webm/opus — a container
//           Safari & co. refuse ("The media resource … was not suitable").
//           The server now runs the operator's pipeline per track:
//             yt-dlp -f bestaudio/best -x --audio-format mp3
//                    --audio-quality 0 -o "<dir>/%(title)s.%(ext)s" URL
//           — audio-only download, universal MP3 at VBR-0 (~245 kbps), the
//           video's real title preserved for the Playing: label. The
//           finished file streams same-origin with full Range support from
//           a per-track workspace dir (30-min sliding TTL + orphan sweeper);
//           /api/audio/stream gained a file-serving mode. Hardening around
//           it: shared failure classifier for both yt-dlp passes (metadata +
//           download), 180 s download budget, 300 MB cap, bot-wall/stale-
//           extractor answers unchanged, ffmpeg-missing degrades to the old
//           proxy path (logged once), queue look-ahead lead 15 s → 60 s so
//           playlist transitions don't stall behind conversions
//   7.4 — Sequence mode: a second mix checkbox next to Random. Ticked, it
//           cycles the scope folder's presets IN ORDER (the tree's exact
//           top-to-bottom order) instead of shuffling — and when it moves
//           past the last preset it wraps back to the first, so the folder
//           loops forever. Random and Sequence are mutually exclusive
//           (ticking either one unticks the other; both share the same
//           delay and folder scope), Random now never loads the same preset
//           twice in a row, and Sequence holds its breath through silence
//           exactly like Random does. The Demo showcase now runs SEQUENCE —
//           the one play-through walks every Zai-Magic preset in order
//           (20 s each) rather than repeating random picks, and when the
//           demo stops, whichever mode it checked is unchecked again
//   7.3 — demo-flow refinements: the Demo Track is a single pass — it plays
//           "Neural Mecha Pulse" once through and stops (a demo, not a radio
//           station). However it ends (natural finish, Stop, or switching to
//           another source) the showcase unwinds: the randomizer the Demo
//           flow force-checked is unchecked again, and the visitor lands
//           back on the "Select an audio source" overlay. Preset-change
//           popups are gone ("Preset loaded" / "Random preset" / "Default
//           preset running") — the footer's SCRIPT: label already echoes
//           every change, so the toasts were pure intrusion; only compile
//           errors still toast. Club-mode randomizer now respects silence:
//           when no music is playing it never re-shuffles the selected
//           preset, even with the checkbox on — it waits for the next track
//   7.2.1 — Supernova (Zai-Magic) preset fix: the particle kill condition
//           (|px|+|py| > 2.4) was physically unreachable — drag caps a
//           particle's total travel at vel/1.6 ≈ 1.0, so nothing ever
//           crossed 1.4, nothing ever died, and since respawning requires a
//           dead particle, the per-beat "budget = n" detonation could never
//           fire after the initial one — the preset exploded once on load,
//           then faded to permanent black. Now every beat force-clears the
//           whole 620-particle field in [beat] (guaranteed full re-detonation
//           on the very same frame), fully-cooled particles die by fade so
//           long beat gaps leave a gentle ember drizzle instead of black,
//           and each blast re-randomizes its geometry (no two explosions
//           alike). Embedded library re-seeded (seed marker 7.01)
//   7.2 — new-visitor showcase flow. Defaults for first-time visitors:
//           the Black + Purple Outline theme with the Blue highlight
//           (previously royal purple + yellow), and Zai-Magic "Bass Bloom"
//           as the startup preset (previously the first Synth-C classic).
//           The idle overlay's Demo Track button now carries an animated
//           reflective shimmer (skewed light band sweeping left→right every
//           3.2 s, reduced-motion safe) to draw the click — and that one
//           click starts the full showcase: the demo track plays while the
//           preset tree selects + expands Zai-Magic, randomize switches on
//           scoped to that folder with a 20-second change interval. Music
//           started with NO preset active (own draft running / selection
//           cleared) auto-loads Bass Bloom. Preset changes — manual load,
//           the random mix, the Demo flow — no longer hard-cut: the engine
//           snapshots the outgoing frame and blur-dissolves it into the new
//           preset over 700 ms (progressive blur + easeOutCubic fade + a
//           slight scale-up so the softening edges never gap; plain
//           crossfade where ctx.filter is unsupported)
//   7.1 — real demo track + a beat detector that survives real music.
//           The Demo button now plays "Neural Mecha Pulse" (the operator's
//           mastered industrial-EDM banger, public/demo-track.mp3, loops
//           gaplessly) instead of the synthetic techno pattern — a real
//           recording is the honest test: deep sub for the bass bands,
//           driving mids, crisp highs, and a kick buried in sustained
//           sub-bass. That last part exposed the 6.x detector as fundamentally
//           broken on mastered music: a LEVEL threshold can never see the
//           kick through the sub (peak-to-mean caps at ~1.2× → sporadic
//           fires, phantom 120-BPM locks from the minInterval floor).
//           v7.1 rewrites detection the way real beat trackers work
//           (aubio/librosa-style): a full-band spectral-flux ONSET envelope
//           → autocorrelation over 300–1000 ms lags with a log-BPM prior →
//           comb-filter phase with grid hysteresis → beats fired on an
//           absolute grid kept glued by a PLL pull. Headlessly validated
//           against the actual track PCM (AnalyserNode chain replicated
//           frame-for-frame): locks the true ~133 BPM (the song drifts
//           130.7→133.1 — the grid TRACKS it) in 1.9 s, 92% beat-gap
//           regularity, confidence 0.99 through the body; techno/hip-hop
//           patterns lock exactly; silence yields zero beats. Known limit:
//           sparse kick-vs-snare backbeats (dnb) may lock half-tempo —
//           stable, and two taps of Set Beat correct it. Visitor-stored
//           beat configs migrate (floorLevel changed units, level → flux).
//           The demo BPM slider is gone (a real track's tempo is detected,
//           not dialed in) — replaced by a track-name chip in the header
//   7.00 — Zai-Magic: ten hand-authored presets in root/embedded/Zai-Magic
//           built around BEAT-SYNCED COLOR — the color wheel turns on the
//           kick, palettes swap per beat / per 4-beat bar, megabuf particles
//           remember the hue of the beat that spawned them + new script
//           tools: hsvr/hsvg/hsvb (HSV→RGB channels), smoothstep and the
//           beatage kick-envelope variable — all documented in the help
//           panel. (Numbered 7.00 rather than 6.10 — a new preset family
//           plus new script-language features is a major release; 6.9.3 was
//           the last patch of the 6.x line.) Beat engine fixes underneath so
//           the Demo track actually
//           locks tempo (was sporadic): demo synth remixed for detection
//           (hot kick owning the 20–100 Hz band, off-beat bassline voiced
//           C3+ with a sidechain pump — chronological envelope events!),
//           and the detector's default threshold 1.4 → 1.2 (the 170 ms FFT
//           window caps a clean kick's peak-to-mean at ~1.5×, so 1.4 fired
//           only sporadically and the BPM never locked)
//   6.9.3 — canonical domain fix: metadataBase/og:url/og:image pointed at
//           openvisualengine.com (a DEAD domain baked in by 6.9.1) while the
//           real site is openvisengine.com — Facebook's "corrupted image"
//           error was its crawler fetching the image from a host that serves
//           nothing; all share URLs now use the correct short domain
//   6.9.2 — share-image fix: og:image re-encoded as BASELINE JPEG (the
//           6.9.1 progressive encoding rendered fine in every browser but
//           Facebook's Sharing Debugger rejected it as "corrupted"), swapped
//           in the title-card artwork (gradient wordmark over three
//           visualizations) and added a ?v=2 cache-bust so crawlers fetch it
//   6.9.1 — social share preview: Open Graph + Twitter Card metadata with
//           a 1200×630 screenshot of the app (public/og-image.jpg) — sharing
//           openvisualengine.com on Facebook/X/WhatsApp/Discord now shows the
//           big image card instead of a bare link
//   6.9 — house account: anonymous visitors play YouTube links through
//         the operator's shared disposable-account cookie (server-side
//         fallback under secrets/, never exposed) — YouTube bot walls stop
//         applying to guests; visitor's own login always wins. Engine fix
//         underneath: Deno runtime shipped in bin/ (YouTube requires a JS
//         runtime for signature/n-challenge solving on authenticated
//         sessions — without it, logged-in extractions return no formats)
//   6.8.2 — login friction cut to ~4 clicks: the exported cookies.txt /
//           Cookie-Editor JSON file can be dragged straight onto the
//           login box (or picked via “Import the exported file…”) — no
//           opening the file, no copy/paste; “Log out” / sign-out
//           revocation note added (the official Google OAuth flow can't
//           power the site: Google's APIs never hand out stream URLs and
//           restricted-scope verification would reject an audio player)
//   6.8.1 — cookie login made foolproof: the login dialog recognizes raw
//           Cookie headers, cookies.txt exports AND Cookie-Editor JSON,
//           validates the paste LIVE through one shared parser (a single
//           cookie's value — like a bare LOGIN_INFO string — gets an honest
//           "this will not log you in" warning), and the how-to steps lead
//           with the one-click extension export for Chrome AND Firefox
//   6.8 — self-healing audio engine: when YouTube changes their mechanics
//         the server detects the stale extractor, updates yt-dlp in the
//         background (verified GitHub release download, atomic swap) and the
//         player retries seamlessly behind an "Updating in Background"
//         notice; bot walls answer "Google login required…" with an Open
//         Settings action, and unfixable failures get the honest
//         "A back-end problem has occurred. Please try again later."
//   6.7 — lazy playlist queue: a playlist link becomes a queue of URLs that
//         streams ONE song at a time (each track is resolved by yt-dlp only
//         right before it plays — next-track look-ahead at ≤15 s to go),
//         queue bar with skip/jump/replay + server-side caps (max 2 parallel
//         extractions); music-service framework: Spotify + Apple Music are
//         registered providers whose playback ships in a later update
//         (logins already save, links answer with an honest notice)
//   6.6 — music service logins (Settings tab): YouTube / YouTube Music,
//         SoundCloud, Spotify, Apple Music cookie login, encrypted on the
//         visitor's computer; Link button gains playlist picking + uses the
//         login to bypass bot walls
//   6.5 — Settings tab (replaces the parked Native tab): theme picker with
//         base chrome (Royal Purple / Matte Black / Black + Purple Outline /
//         Light) × selectable highlight color (Purple, Yellow, Blue, Green,
//         Red, Orange), all per-visitor; simple OVE logo as the site favicon
//   6.4 — beat detection suspends when no music is playing/loaded (no ghost
//         beats after Stop, BPM resets) + dark theme restyle: royal purple
//         chrome with light-yellow highlights
//   6.3 — light/dark theme tick switch in the header (white theme via .light
//         palette remap; per-visitor, persisted by next-themes)
//   6.2 — security hardening: read-only embedded library (server refuses all
//         writes) + per-visitor "user created" presets stored in the browser
//   6.1 — preset library quality pass: every embedded stand-in is now a UNIQUE
//         generated visual (16 families × seeded parameters), approx badge
//   6.0 — renamed to "Open Visualization Engine" + footer version stamp
//   5.0 — folder-tree Presets page (Task 9–11 state, restored in Task 12)
//   4.0 — link audio source (yt-dlp resolve + stream proxy)

export const APP_NAME = 'Open Visualization Engine'
export const APP_SHORT = 'OVE'
export const APP_VERSION = '7.19.0'