Play the music and sound effects from the ROM's sound engine (Closes #34)

The sound engine (audio/engine.asm, home/audio.asm) is ported on a byte
copy of its audio WRAM and a sound register model. A reference test runs
the cartridge's routines beside it and matches the WRAM and registers
after every UpdateSound for all songs, effects and cries, fades, the
danger tone and effect priority. apu.ts synthesizes the four channels in
an AudioWorklet; its output matches the reference emulator's APU by
spectrum. The world runs the engine twice per tick; Play or the first
press unlocks sound, pausing suspends it, Settings sets the volume.

Wired in: map music by map setup and special map music, script audio
commands, text fanfares, WaitSFX and cries that hold the script frozen
(the last page stays shown), battle music, cries, fainting, victory,
capture and the low HP tone, Pokémon Center healing, evolution, the
intro, the Pokédex's cries, PCs, marts, healing items, talk and menu
clicks, bumps, ledges, warps, boulders, the Bicycle and Surf.

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

src/main.ts

@@ -11,6 +11,8 @@ import { renderPokedexScreen, renderPokedexTab } from "./ui/pokedex";
 import {
   RESERVED_KEYS,
   TEXT_SCALES,
+  VOLUMES,
+  type Volume,
   applyTextScale,
   buttonKeys,
   defaultPreferences,
@@ -93,7 +95,12 @@ function showWorld(world: GameWorld) {
   get("town-map-view").hidden = !world.townMap;
   if (world.townMap)
     drawTownMap(get<HTMLCanvasElement>("town-map-canvas"), world);
-  const dialogue = world.dialogue;
+  // While a script waits for its sound, the last page stays in the box.
+  const dialogue =
+    world.dialogue ??
+    (world.waitingPage !== undefined
+      ? { pages: [world.waitingPage], index: 0, holdTicks: 0 }
+      : undefined);
   showPicture(world);
   // A page without text is a button wait while a picture is shown.
   const pictureWait = Boolean(
@@ -1696,6 +1703,7 @@ const input = new InputController((button, pressed) =>
 let preferences = loadPreferences();
 let keys = keyMap(preferences);
 applyTextScale(preferences.textScale);
+runtime.setVolume(preferences.volume);
 const controls = bindControls(
   root,
   input,
@@ -2021,6 +2029,7 @@ function setPreferences(next: Preferences, status = "") {
   keys = keyMap(preferences);
   savePreferences(preferences);
   applyTextScale(preferences.textScale);
+  runtime.setVolume(preferences.volume);
   get("game-screen").setAttribute("aria-label", `Game screen. ${controlsSummary()}`);
   showSettings();
   get("settings-status").textContent = status;
@@ -2028,6 +2037,8 @@ function setPreferences(next: Preferences, status = "") {
 function showSettings() {
   for (const radio of document.querySelectorAll<HTMLInputElement>('input[name="text-scale"]'))
     radio.checked = Number(radio.value) === preferences.textScale;
+  for (const radio of document.querySelectorAll<HTMLInputElement>('input[name="volume"]'))
+    radio.checked = Number(radio.value) === preferences.volume;
   get("key-table").replaceChildren(
     ...BUTTON_ORDER.map((button) => {
       const row = document.createElement("tr"),
@@ -2112,6 +2123,12 @@ for (const radio of document.querySelectorAll<HTMLInputElement>('input[name="tex
     if (TEXT_SCALES.includes(scale))
       setPreferences({ ...preferences, textScale: scale }, `Text size: ${radio.parentElement?.textContent?.trim()}.`);
   });
+for (const radio of document.querySelectorAll<HTMLInputElement>('input[name="volume"]'))
+  radio.addEventListener("change", () => {
+    const volume = Number(radio.value) as Volume;
+    if (VOLUMES.includes(volume))
+      setPreferences({ ...preferences, volume }, `Sound: ${radio.parentElement?.textContent?.trim()}.`);
+  });
 get("reset-keys").addEventListener("click", () =>
   setPreferences({ ...preferences, keys: defaultPreferences().keys }, "Controls reset to the defaults."),
 );