fix(playback): withdraw the keep-awake vote when the renderer crashes

A crash emits render-process-gone while the WebContents object stays
alive, so the destroyed listener alone missed it: without a follow-up
reload the display stayed pinned awake. Review finding by Codex.

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

apps/electron-backend/src/app/services/playback-keep-awake.service.spec.ts

@@ -98,6 +98,17 @@ describe('playback keep-awake service', () => {
         expect(mockedBlocker.stop).toHaveBeenCalledWith(7);
     });
 
+    it('releases the blocker when the renderer process crashes', () => {
+        const stub = createSenderStub(1);
+
+        setPlaybackKeepAwake(stub.sender, true);
+        // A crash emits render-process-gone while the WebContents object
+        // stays alive; without a reload no other lifetime event follows.
+        stub.emit('render-process-gone', {}, { reason: 'crashed' });
+
+        expect(mockedBlocker.stop).toHaveBeenCalledWith(7);
+    });
+
     it('releases the blocker on a main-frame navigation (reload)', () => {
         const stub = createSenderStub(1);
 
@@ -127,10 +138,12 @@ describe('playback keep-awake service', () => {
 
         setPlaybackKeepAwake(stub.sender, true);
         expect(stub.listenerCount('destroyed')).toBe(1);
+        expect(stub.listenerCount('render-process-gone')).toBe(1);
         expect(stub.listenerCount('did-start-navigation')).toBe(1);
 
         setPlaybackKeepAwake(stub.sender, false);
         expect(stub.listenerCount('destroyed')).toBe(0);
+        expect(stub.listenerCount('render-process-gone')).toBe(0);
         expect(stub.listenerCount('did-start-navigation')).toBe(0);
     });
 

apps/electron-backend/src/app/services/playback-keep-awake.service.ts

@@ -13,8 +13,10 @@ import { powerSaveBlocker, WebContents } from 'electron';
  *
  * The renderer's flag must not outlive the page that set it: a reload or a
  * crashed render process would otherwise pin the display awake until app
- * quit. Each activating WebContents therefore gets destroy/navigation
- * listeners that withdraw its vote.
+ * quit. Each activating WebContents therefore gets destroy/crash/navigation
+ * listeners that withdraw its vote — a crash emits `render-process-gone`
+ * while the WebContents object stays alive, so `destroyed` alone would miss
+ * it when no reload follows.
  */
 
 const activeSenders = new Set<number>();
@@ -62,9 +64,11 @@ function watchSenderLifetime(sender: WebContents): void {
         }
     };
     sender.on('destroyed', clear);
+    sender.on('render-process-gone', clear);
     sender.on('did-start-navigation', onNavigation);
     senderCleanups.set(senderId, () => {
         sender.off('destroyed', clear);
+        sender.off('render-process-gone', clear);
         sender.off('did-start-navigation', onNavigation);
     });
 }