fix(sim): boot silent (video off, audio 0) — no un-gestured auto-start

The post-load autoStart() flipped Video on and lifted audio to 3/10 with no
user gesture. Browser autoplay policy blocks an audio play() made outside a
gesture (muted video survives, sound does not), so auto-start showed video but
stayed silent. Boot SILENT instead and wait for the operator to turn Video on —
that click IS the gesture, and its handler couples audio to 3/10 and starts the
soundtrack in-gesture, so sound reliably comes up with video.

Updates the pytest e2e + Playwright e2e specs to assert boot-silent + the
video-on-couples-audio wiring instead of the old auto-start wiring.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

simulator/e2e/tests/altitude-lock.spec.ts

@@ -83,13 +83,14 @@ test("audio is a 0-10 level dial", async ({ page }) => {
   expect(ctl.max).toBe("10");
 });
 
-test("the experience auto-starts once loaded: video on + audio at 3/10", async ({ page }) => {
+test("boots silent (video off, audio 0); turning video on couples audio to 3/10", async ({ page }) => {
   await boot(page);
-  // No gesture needed — autoStart() flips Video on and lifts audio to a gentle level
-  // the moment the preload finishes.
-  await expect.poll(() => page.evaluate(() => (document.querySelector("#visual") as HTMLInputElement).checked)).toBe(true);
+  // Boots SILENT — no un-gestured auto-start, so the browser autoplay block never bites.
+  expect(await page.evaluate(() => (document.querySelector("#visual") as HTMLInputElement).checked)).toBe(false);
+  expect(await page.evaluate(() => (document.querySelector("#audio") as HTMLInputElement).value)).toBe("0");
+  // Turning Video on (a click gesture) lifts the audio dial to a gentle 3/10.
+  await enableVideo(page);
   await expect.poll(() => page.evaluate(() => (document.querySelector("#audio") as HTMLInputElement).value)).toBe("3");
-  // The level label reflects it.
   expect(await page.evaluate(() => document.querySelector("#audio-level-val")?.textContent)).toBe("3");
 });
 

simulator/static/app.js

@@ -1260,8 +1260,12 @@ async function main() {
   $("stage").addEventListener("wheel", onWheel, { passive: false });
   update();                   // render the initial state (both toggles off → black, silent)
   await preloadAllMedia();    // download all media, updating the loading bar
-  hideLoading();              // experience is ready to run smoothly
-  autoStart();                // once loaded: video on + gentle audio (3/10), no gesture needed
+  hideLoading();              // experience is ready — boots SILENT (video off, audio 0)
+  // No un-gestured auto-start: a browser autoplay policy blocks an audio play() made
+  // outside a user gesture (muted video survives, sound does not), so an auto-start
+  // would show video but stay silent. Instead the experience waits for the operator to
+  // turn Video on — that click IS the gesture, and its handler (above) lifts audio to
+  // 3/10 and starts the soundtrack in-gesture, so sound reliably comes up with video.
 }
 
 // Populate the language dropdown from the registry and wire live switching.
@@ -1297,16 +1301,4 @@ function setLanguage(lang) {
   if (lastAffect) renderAffect(lastAffect.strength, lastAffect.intensity, lastAffect.right);
 }
 
-// Auto-start the experience the moment media is ready: bring Video on and the audio
-// level to 3/10 (the same gentle default the first manual Video-on couples in). The
-// audio <audio> elements ideally unlock inside a user gesture (Safari); this fires
-// outside one, so a browser with a strict autoplay policy may BLOCK the first audio
-// play() until any interaction — the on-screen audio status readout will show it.
-function autoStart() {
-  $("visual").checked = true;
-  videoEverOn = true;
-  if (audioLevel() === 0) { $("audio").value = "3"; updateAudioLevelLabel(); }
-  applyAudio();
-  update();
-}
 main();