feat(audio): per-altitude soundtracks + separated audio/visual controls spec

Sound for the experience, plus the design to control it.

Soundtrack layer (ambience), all license-clean (PD/CC0), recorded in
docs/audio-candidate-pool.md (media gitignored; re-sourceable):
- cosmos: Pillars of Creation sonification (NASA, PD)
- orbit:  station room-tone hum (CC0)
- coast:  sea waves + terns (CC0)
- reef:   6-layer NOAA soundscape + CC0 submerged bed (PD + CC0)
- abyss:  blue-whale moan (NOAA, PD)

Solution Design (proposed): split the bundled Content selector into two
orthogonal dials, Visual (on/off) x Audio (off/soundtrack/white-noise),
unlocking white-noise+video. Soundtrack follows the single Altitude dial;
white noise is altitude-independent. Reframes the networked-control-surface
spec SS3/SS5 (still proposed/unbuilt -> clean pre-impl edit). Music layer deferred.

Dev panel: links to the clip + audio review galleries; sticky stage/panel layout.
gitignore: audio media, review_audio.html, .DS_Store.

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

simulator/static/index.html

@@ -83,6 +83,12 @@
           <legend>Cache &amp; playback</legend>
           <dl id="dev-stats" class="dev-dl"></dl>
         </fieldset>
+
+        <fieldset>
+          <legend>Review galleries</legend>
+          <a class="dev-link" href="/review.html" target="_blank" rel="noopener">🎞️ Clip pool review</a>
+          <a class="dev-link" href="/review_audio.html" target="_blank" rel="noopener">🔊 Audio pool review</a>
+        </fieldset>
       </div>
     </section>
   </main>

simulator/static/style.css

@@ -2,8 +2,9 @@
 body { margin: 0; font: 14px/1.4 system-ui, sans-serif; background: #111; color: #eee; }
 header { padding: 0.6rem 1rem; background: #000; }
 h1 { font-size: 1rem; margin: 0; font-weight: 600; }
-main { display: flex; gap: 1rem; padding: 1rem; flex-wrap: wrap; }
-.stage { flex: 1 1 640px; }
+main { display: flex; gap: 1rem; padding: 1rem; flex-wrap: wrap; align-items: flex-start; }
+/* Stage stays pinned in view while the right pane scrolls on its own. */
+.stage { flex: 1 1 640px; position: sticky; top: 1rem; }
 .screen { position: relative; width: 100%; aspect-ratio: 16 / 9; background: #000;
           border-radius: 6px; overflow: hidden; }
 #vid { width: 100%; height: 100%; object-fit: cover; transition: opacity 0.15s ease; }
@@ -41,7 +42,9 @@ main { display: flex; gap: 1rem; padding: 1rem; flex-wrap: wrap; }
 .hud-status { fill: #8fdcff; font: 2.4px monospace; opacity: 0.9; letter-spacing: 0.15px; }
 .black { position: absolute; inset: 0; background: #000; opacity: 1; transition: opacity 200ms ease; }
 .hidden { display: none; }
-.panel { flex: 0 0 280px; display: flex; flex-direction: column; gap: 0.8rem; }
+.panel { flex: 0 0 280px; display: flex; flex-direction: column; gap: 0.8rem;
+         max-height: calc(100vh - 2rem); overflow-y: auto;
+         position: sticky; top: 1rem; }
 fieldset { border: 1px solid #333; border-radius: 6px; }
 legend { color: #9af; padding: 0 0.4rem; }
 label { display: block; margin: 0.4rem 0; }
@@ -87,6 +90,10 @@ input[type=range], select { width: 100%; }
 .dev-btn { margin-top: 0.5rem; width: 100%; padding: 0.4rem; cursor: pointer;
            background: #182028; color: #cde; border: 1px solid #2c3c5c; border-radius: 4px; }
 .dev-btn:hover { background: #20303f; }
+.dev-link { display: block; margin-top: 0.4rem; padding: 0.4rem; text-align: center;
+            background: #182028; color: #cde; border: 1px solid #2c3c5c; border-radius: 4px;
+            text-decoration: none; }
+.dev-link:hover { background: #20303f; }
 .dev-dl { margin: 0; display: grid; grid-template-columns: auto 1fr; gap: 0.15rem 0.6rem; font-size: 12px; }
 .dev-dl dt { color: #789; }
 .dev-dl dd { margin: 0; color: #dde; word-break: break-word; }