fix: managed playback overlay lifecycle for launcher-owned sessions

- Remove --background from launcher-owned mpv starts; quit only non-tray/non-background managed sessions
- Defer autoplay-ready signal until overlay window content is loaded; retry after flush
- Retry socket availability before auto-starting overlay (up to 25 attempts, 200ms apart)
- Extract warm tokenization signal into autoplay-tokenization-warm-release with stale-media guard
- Queue second-instance commands until app ready runtime completes
- Guard globalShortcut cleanup with isAppReady check to avoid pre-ready crash
- Recognize "osx" as a macOS platform alias in Lua environment detection

src/main/runtime/app-lifecycle-main-cleanup.ts

@@ -22,6 +22,7 @@ export function createBuildOnWillQuitCleanupDepsHandler(deps: {
   stopConfigHotReload: () => void;
   restorePreviousSecondarySubVisibility: () => void;
   restoreMpvSubVisibility: () => void;
+  isAppReady: () => boolean;
   unregisterAllGlobalShortcuts: () => void;
   stopSubtitleWebsocket: () => void;
   stopTexthookerService: () => void;
@@ -63,7 +64,10 @@ export function createBuildOnWillQuitCleanupDepsHandler(deps: {
     stopConfigHotReload: () => deps.stopConfigHotReload(),
     restorePreviousSecondarySubVisibility: () => deps.restorePreviousSecondarySubVisibility(),
     restoreMpvSubVisibility: () => deps.restoreMpvSubVisibility(),
-    unregisterAllGlobalShortcuts: () => deps.unregisterAllGlobalShortcuts(),
+    unregisterAllGlobalShortcuts: () => {
+      if (!deps.isAppReady()) return;
+      deps.unregisterAllGlobalShortcuts();
+    },
     stopSubtitleWebsocket: () => deps.stopSubtitleWebsocket(),
     stopTexthookerService: () => deps.stopTexthookerService(),
     clearWindowsVisibleOverlayForegroundPollLoop: () =>