Play a sound through a graph of gain, pitch and EQ effects #311

A sound could only be played as it was uploaded. A Sound FX asset is
a node graph like a shader: Input, effects, Output. Play sound has a
new input fx that sends the voice through it.

- New asset type soundfx ("Sound FX"), not placeable, with a graph
  and its own tab. The heading in the asset panel is "Sound effects",
  so it does not take the click meant for the + menu entry.
- Nodes in core/soundfx/nodes.ts, category sound, port type audio
  that only fits audio: Input, Output, Gain (dB), Pitch (semitones),
  EQ (80 Hz and 12 kHz shelves, peaks at 250 Hz, 1 kHz and 4 kHz).
- compileSoundFx walks back from the Output with the shared graph
  emitter. An input takes one edge, so the result is one line: a
  pitch and a list of gain and filter stages. A node without input
  or a graph without Output reports a problem on the node.
- Pitch is the playback rate of the source. It applies to the whole
  sound and also changes its length, the node description says so.
- The BehaviorSystem resolves fx and hands the line to the AudioSink.
  An fx that is missing or does not compile plays the sound dry.
- SoundLibrary wires source, stages, volume, destination in that
  order. stats().last now also names pitch and stage count.
- The tab header picks one of the project's sounds and plays it
  through the graph as it stands. Stop there ends only its own voice.

Tests:
- soundfx.test.ts (new, 11), sound-library (9, +2 for the wiring),
  node-catalog (+1 for fx), graph and asset-groups adjusted
- e2e 34: ALL PASSED - 26 checks (+5: + menu opens the tab, palette,
  2 effects, tab Play and game Play through the FX at -12 st)
- Gate on melektaus-atx: typecheck, lint, prettier clean, 239 of 240
  test files green. The red one was sound-library (its fake
  AudioContext had no playbackRate), fixed afterwards, gate not
  re-run in full.
- Counter-check: without the audio rule in portsCompatible the port
  test fails.

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

src/runtime/systems/Audio.ts

@@ -1,3 +1,5 @@
+import type { FxChain } from '../../core/soundfx/nodes';
+
 /**
  * What the runtime needs of the outside world to make a noise – the counterpart of `Input` on the
  * way out. The browser side of it is `viewport/SoundLibrary`; a test (and a run started before
@@ -11,9 +13,10 @@ export interface AudioSink {
    * Starts one voice. `volume` is final (0–1) and every call overlaps whatever is already playing.
    * `owner` is the behavior the sound belongs to: when that behavior is destroyed the voice goes
    * with it, because a sound is something a thing in the world is doing, not a thing of its own.
-   * `''` means the voice has no owner and outlives whatever started it.
+   * `''` means the voice has no owner and outlives whatever started it. `fx` is the line of effects
+   * the voice passes on its way out (#311); `DRY` passes none.
    */
-  play(file: string, volume: number, loop: boolean, owner: string): void;
+  play(file: string, volume: number, loop: boolean, owner: string, fx?: FxChain): void;
   /** Silences every voice of that file; `''` silences all of them. */
   stop(file: string): void;
   /** Silences every voice started by that owner – what destroying a behavior does. */