Refactoring round 10: split SoundLibrary, fold sound duplicates (#85)

Refactoring round 10 covers everything since round 9 (808e1ee): 110
commits with about 47 000 new lines, nearly all of them sound, sound
FX, instruments, patterns and songs. Behaviour is unchanged.

Duplicate code (jscpd over src, 50 tokens, TypeScript only, measured
on 808e1ee and here alike: 47 clones / 426 lines before, 33 / 245
after; round 9 itself ended at 22 / 160 by this count):

- PreviewParams (new, editor/soundfx) is the header's parameter bar
  of the Sound FX and the Instrument tab: values, defaults, fields
  and the voices a moved field reaches. Both tabs had it line for
  line.
- fxWorklet: an Effect base runs the bit crusher, phaser, flanger,
  limiter, LFO and bus shifter, a Source base the pitch player and
  the Chip. Start is the one wait for a voice's first sample, which
  four processors wrote out each.
- nodes/shared has checkPort, detachedPort, fxParamsPort and
  letRingPort. The Play and Stop nodes of sounds, notes, patterns and
  songs spelled each port out, up to five times.
- parameterValues builds both Sound FX parameters and Instrument
  parameters, which differed in name and text only.
- SetLoopCommand sets the ruler loop of a pattern or a song. It
  replaces SetPatternLoopCommand and SetSongLoopCommand.
- addLink in music/routing is the one rule for a link that both the
  song routing and the Master routing keep.
- eqCurves works out each band and their sum for the EQ tab, which
  did that in its drawing code. It replaces eqCurveDb, which only a
  test called.
- Smaller ones: the eight neighbour directions of a tile cell, and
  drawFloatingBox for the shadowed box of Popup and FloatWindow.
- Left on purpose: Play pattern and Play song stay two parallel node
  definitions, and the smaller clones under ten lines stay.

Architecture:

- SoundLibrary.ts goes from 2897 to 2188 lines. What a stage of a
  sound FX becomes as Web Audio nodes, and how the knobs of a playing
  voice move, is now viewport/fxNodes.ts. None of it keeps state of
  the library.

Dead code (TS language service, references per export and member):

- soundRefIds, LFO_SHAPE_INDEX, TREMOLO_ROWS, VIBRATO_ROWS and
  REVERB_ROWS had no reader. The four routing node defs are
  registered without an unused exported name.
- soundFileOf and portTypeOf were called by tests only. The tests
  now ask findSound and portOf, which the editor uses. DRY moves
  from src into the one test that uses it.
- 51 values used only in their own file lose their `export`. Types
  and the node catalogues stay exported.
- Kept on purpose: neighboursOf is the cell by cell reading the
  indexed neighboursIn is checked against, and PitchShifter.latency
  is the test's one view of how late the shifter is.

Comments and docs:

- Seven comments told history ("no longer", "any more", "as
  before", "of before #354"). Nine comment blocks ran far past the
  line width. Proof that this changed no code: the bundle was md5
  identical, and the touched tests and e2e modules were identical
  after esbuild.
- README: sound FX, instrument, pattern, song and bus in the asset
  list, the pages Instruments, Patterns and Songs, 1919 checks.
- Wiki: see its own commit.

Tests:

  Gate (melektaus-atx)    274 files, 4236 tests, CHECK EXIT 0
  e2e 34, 64, 65          ALL PASSED, 180 checks
  Unit, touched areas     16 files, 804 tests

No check was added, the e2e sum stays at 1919. Counter-checks, each
put back by copy and compared with cmp:

- addLink without the loop rule: 2 tests fail, one per routing.
- eqCurves with the sum of the last band only: 1 test fails.
- Start in the worklet never waiting: e2e 34 fails in exactly the
  four checks that hang on a voice's first sample (Flanger, Tremolo,
  Chip, a pitched note planned ahead).

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/core/graph/nodes/shared.ts

@@ -14,6 +14,15 @@ export const any = (key: string, label = key): PortDef => ({ key, label, type: '
 
 export const withDefault = (port: PortDef, value: PropertyValue): PortDef => ({ ...port, default: value });
 
+/** A boolean input that shows a check box while it is not connected. */
+export const checkPort = (key: string, label: string, fieldLabel: string, value = false): PortDef => ({
+  key,
+  label,
+  type: 'boolean',
+  default: value,
+  field: { key, label: fieldLabel, kind: 'boolean', default: value },
+});
+
 /** A whole-number input (an index, a count): its field shows no decimals, the node floors it anyway. */
 export const int = (key: string, value = 0, label = key): PortDef => ({
   key,
@@ -58,13 +67,7 @@ export const PER_CELL_INPUT = 'perCell';
  * Which pairs a collision event hears of a map's trigger tiles (#160): off, one per area of a tile –
  * a pond is entered once –, on, one per cell.
  */
-export const perCellPort = (): PortDef => ({
-  key: PER_CELL_INPUT,
-  label: 'per cell',
-  type: 'boolean',
-  default: false,
-  field: { key: PER_CELL_INPUT, label: 'Per cell (trigger tiles)', kind: 'boolean', default: false },
-});
+export const perCellPort = (): PortDef => checkPort(PER_CELL_INPUT, 'per cell', 'Per cell (trigger tiles)');
 
 /**
  * The trigger tile a collider lies on (#160) and its cell in the map, which is then `other`. No
@@ -127,6 +130,24 @@ export const busPort = (none: string, master: boolean): PortDef => ({
 /** The `bus` input of a Play node: empty is the bus its asset names. */
 export const playedBusPort = (): PortDef => busPort('From the asset', true);
 
+/**
+ * The way out of the ownership rule, off by default. Needed for one shape that is common enough to
+ * deserve it: an object that plays its own death sound and destroys itself in the same flow – the
+ * voice would be cut off in the instant it started, because the behavior holding it is gone.
+ */
+export const detachedPort = (): PortDef =>
+  checkPort('detached', 'detached', 'Detached (outlives this object)');
+
+/** Values for the parameters of a sound FX or an instrument, bundled by their node (#311, #331). */
+export const fxParamsPort = (key = 'fxParams', label = 'fx params'): PortDef => ({
+  key,
+  label,
+  type: 'fxparams',
+});
+
+/** Whether a Stop node lets what it stops fall away in its release instead of cutting it. */
+export const letRingPort = (): PortDef => checkPort('letRing', 'let ring', 'Let ring');
+
 export function binaryMath(type: string, description: string, fn: (a: number, b: number) => number): NodeDef {
   return {
     type,