Put a sound in a room, a hall or a cave with a Reverb node (#328)

A sound FX had no space around it. The Reverb node folds the sound
with an impulse response: one it makes itself, or a sound asset as the
answer of a real space. It works on a voice and on a bus.

- Type: Room, Hall, Cave and Plate have fixed numbers. Custom shows
  Decay (up to 10 s), Damping and Pre-delay. Sound shows the pick of a
  sound asset and Pre-delay. The rows are derived ports, the sound pick
  an idle param, so they only appear for their type.
- The made impulse response is seeded noise per side, 60 dB down at
  Decay, through a low-pass closing from 20 kHz toward 500 Hz as far
  as Damping says. It is made once per rate, decay and damping, the
  last 16 are kept.
- A sound as impulse response: the sound FX compilers now get the
  project, so a node can turn a sound asset into its file. The build
  key holds that file, so a cut or swapped sound builds again. The
  instrument compiler does the same for a Reverb inside an instrument.
- The library loads that file with the voice, a sequence or before a
  bus builds its chain. A missing file leaves the reverb silent.
- Mix blends dry and reverb and is the only number that moves while
  the sound plays, as the issue said. The voice rings for pre-delay
  plus decay, or as long as its sound.
- The open point from #325 about sends on project buses is #351, not
  part of this.

Tests:
- Unit reverb (new) 4, soundfx 57 (4 new), sound-library 104 (2 new),
  green.
- Counter-checks, each turns one test red: the impulse file not loaded
  with the voice, the tail without the length of the sound.
- e2e 34 (melektaus-atx): ALL PASSED, 81 checks (1 new). Chrome
  offline: silent during the pre-delay, 35.9 dB fall over 0.6 s of a
  1 s decay (36 expected), the dry half at 0.25 for mix 0.5. A sound
  with one sample at 0.2 s gives the impulse back 0.25 s later and
  nowhere else.
- Gate (melektaus-atx) over the end of this series #318 to #328:
  CHECK EXIT 0, 267 files, 4134 tests.

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

src/editor/debugHook.ts

@@ -82,10 +82,11 @@ export function installDebugHook(app: Application, state: EditorState, editor: E
       sampleRate: () => soundLibrary.liveContext().sampleRate,
       /**
        * The nodes a stage of a voice becomes, in any context – an offline one renders what it does.
-       * `at` is when its voice starts, which a Flanger's sweep counts from (#341).
+       * `at` is when its voice starts, which a Flanger's sweep counts from (#341), `impulse` the
+       * sound a Reverb that takes one has (#328).
        */
-      stageNodes: (context: BaseAudioContext, stage: FxStage, at?: number) =>
-        stageNodes(context, stage, undefined, at),
+      stageNodes: (context: BaseAudioContext, stage: FxStage, at?: number, impulse?: AudioBuffer) =>
+        stageNodes(context, stage, undefined, at, impulse),
       /** The gain in dB a Saturation's auto-gain gives at a drive (#323). */
       saturationAutoGain,
       /** What drives the two shares of a Mix "Both at center", in any context (unstarted). */

src/editor/graph/GraphCanvas.ts

@@ -311,7 +311,7 @@ export class GraphCanvas extends Widget {
         : asset.type === 'particles'
           ? particleLibrary.buildFor(asset).problems
           : asset.type === 'soundfx'
-            ? soundFxBuildFor(asset).problems
+            ? soundFxBuildFor(asset, this.state.project).problems
             : asset.type === 'instrument'
               ? instrumentCheck(asset, instrumentSourcesOf(this.state.project)).problems
               : asset.type === 'song'

src/editor/soundfx/SoundFxEditor.ts

@@ -100,7 +100,7 @@ export class SoundFxEditor extends AssetTabEditor<SoundFxAsset, GraphCanvas> {
   play(): void {
     const asset = this.asset();
     const sound = findAssetOf(this.state.project, this.previewSoundId, 'sound');
-    const plan = asset && soundFxBuildFor(asset).compiled;
+    const plan = asset && soundFxBuildFor(asset, this.state.project).compiled;
     if (!sound?.file || !plan) return;
     const props = resolveAssetProps(this.state.project, sound);
     const fx = { plan, params: { ...this.values } };
@@ -123,7 +123,7 @@ export class SoundFxEditor extends AssetTabEditor<SoundFxAsset, GraphCanvas> {
   }
 
   protected override infoText(asset: SoundFxAsset): string {
-    const build = soundFxBuildFor(asset);
+    const build = soundFxBuildFor(asset, this.state.project);
     if (!build.compiled) return build.reason;
     return `${build.effects} ${build.effects === 1 ? 'effect' : 'effects'}`;
   }
@@ -133,7 +133,9 @@ export class SoundFxEditor extends AssetTabEditor<SoundFxAsset, GraphCanvas> {
     const sound = findAssetOf(this.state.project, this.previewSoundId, 'sound');
     this.soundPicker.setText(sound?.name ?? 'No sound');
     this.soundPicker.setEnabled(Boolean(asset && sound));
-    this.playButton.setEnabled(Boolean(asset && sound?.file && soundFxBuildFor(asset).compiled));
+    this.playButton.setEnabled(
+      Boolean(asset && sound?.file && soundFxBuildFor(asset, this.state.project).compiled),
+    );
     this.stopButton.setEnabled(Boolean(asset));
     this.syncParams(asset);
   }