Merge origin/fix/asio-all-app-audio (teammate teardown fix)

Kept theirs: fresh loopback context per session + close() on teardown
(orphaned-worklet fix) and its test. Kept ours: deferred debug-gated
install lines, cache-control, decision-vector diag.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

static/app.js

@@ -5468,7 +5468,9 @@ window.addEventListener('unhandledrejection', (e) => {
             throw new Error('no loopback audio track');
         }
         try {
-            _lbCtx = _lbCtx || new AudioContext();
+            // Fresh context per session (not reused) so teardown's close()
+            // fully releases the tap worklet node — see _teardownLoopback.
+            _lbCtx = new AudioContext();
             if (_lbCtx.state !== 'running') await _lbCtx.resume().catch(() => {});
             const source = _lbCtx.createMediaStreamSource(stream);
             const tap = _makeTap(_lbCtx);
@@ -5495,6 +5497,13 @@ window.addEventListener('unhandledrejection', (e) => {
         if (_lbTap) _lbTap.active = false;
         if (_lbStream) for (const t of _lbStream.getTracks()) t.stop();
         _lbStream = null; _lbTap = null;
+        // Close the capture context so its tap worklet node is released. The
+        // context is per-session (not reused): without this, each exclusive⇄
+        // shared switch orphaned a live worklet on a long-lived context.
+        if (_lbCtx) {
+            try { await _lbCtx.close(); } catch (_) { /* already closed */ }
+            _lbCtx = null;
+        }
         if (_lbPageMuted && typeof api.setPageMuted === 'function') {
             try { await api.setPageMuted(false); } catch (_) { /* engine gone */ }
         }
@@ -5623,24 +5632,6 @@ window.addEventListener('unhandledrejection', (e) => {
             }
 
 
-            // [asio-diag] full decision vector, change-gated (500ms poll —
-            // steady state must not flood the buffer). This is the feeder-side
-            // counterpart of the watcher's [feedpak-route] decision line: it
-            // shows WHY the bus did or didn't engage (exclusive predicate,
-            // stems graph presence, native transport ownership, element song).
-            if (window._asioDiagEnabled?.()) {
-                const d = 'running=' + running + ' exclusive=' + exclusive
-                    + ' stems=' + !!stems + ' songAudio=' + !!songAudio
-                    + ' juceMode=' + !!window._juceMode
-                    + ' elementSong=' + elementSong
-                    + ' want=' + want + ' mode=' + _mode;
-                if (d !== window._lastRendererBusDecision) {
-                    window._lastRendererBusDecision = d;
-                    console.log('[asio-diag] renderer-bus:', d);
-                }
-            }
-
-
             const stemsGraphChanged = _mode === 'stems' && stems !== _stemsGraph;
             if (want !== _mode || stemsGraphChanged) {
                 await _disengage();

tests/js/renderer_bus_feeder.test.js

@@ -54,6 +54,7 @@ function makeFakeContext(sampleRate = 48000) {
             this.mediaStreamSource = stream;
             return { connect() {}, disconnect() {} };
         },
+        close() { this.closed = true; return Promise.resolve(); },
     };
     return ctx;
 }
@@ -231,6 +232,22 @@ test('exclusive output + loopback available → engages without any song loaded'
     assert.equal(sb.__calls.setPageMuted.length, 0, 'suppress constraint honoured — no page mute');
 });
 
+test('loopback context is closed on disengage (no orphaned tap worklet)', async () => {
+    let excl = true;
+    const stream = makeLoopbackStream();
+    const sb = makeSandbox({ exclusive: () => excl, displayMedia: () => Promise.resolve(stream) });
+
+    await sb.window._reevaluateRendererBus();          // engage loopback
+    const lbCtx = sb.__createdContexts.at(-1);
+    assert.equal(lbCtx?.mediaStreamSource, stream, 'loopback engaged');
+    assert.notEqual(lbCtx.closed, true, 'context live while engaged');
+
+    excl = false;
+    await sb.window._reevaluateRendererBus();          // disengage
+    assert.equal(lbCtx.closed, true, 'loopback context closed on disengage');
+    assert.ok(stream.__stopped.includes('audio'), 'capture stream stopped');
+});
+
 test('loopback preferred over stems when both available', async () => {
     const stream = makeLoopbackStream();
     const sb = makeSandbox({ exclusive: () => true, displayMedia: () => Promise.resolve(stream) });