fix(plugin): keep loading OSD off on warm playlist advance (#317)

* fix(plugin): keep loading OSD off on warm playlist advance

- Track overlay_content_ready_seen when the app sends subminer-overlay-loading-ready
- Skip restarting the "Overlay loading" spinner for an overlay that already reported ready, so it no longer times out into "Overlay did not become ready" (#315)
- Reset the flag on stop, restart, start failure and shutdown
- Add start-gate tests for warm and not-yet-ready playlist advances

* fix(plugin): only report overlay ready once content has loaded

Hide paths dismissed the loading OSD with subminer-overlay-loading-ready,
which the plugin now remembers to skip the spinner on later playlist files.
A hide before the overlay had content would wrongly mark it ready. The app
now sends ready only when the overlay window content is ready, and a new
stop-only subminer-overlay-loading-dismissed message otherwise.

* fix(plugin): resync overlay readiness on dismissal and mpv connect

A dismissal now clears the plugin's readiness flag, since the app sends it
only while its overlay window has no content (e.g. a replaced window).
On mpv (re)connect the app resends subminer-overlay-loading-ready when the
overlay already has content, so a ready signal lost while mpv was away, or
sent before this mpv's plugin existed, still reaches the plugin.

* refactor(main): pass overlay readiness handler directly

src/main/assemblies/playback.test.ts

@@ -153,6 +153,7 @@ function makeDeps(recorder: Recorder): PlaybackAssemblyDeps {
     ),
     requestAppQuit: spy('requestAppQuit', noop),
     maybeStartOverlayLoadingOsd: spy('maybeStartOverlayLoadingOsd', noop),
+    reportOverlayContentReadyToPlugin: spy('reportOverlayContentReadyToPlugin', noop),
     flushQueuedMpvOsdNotifications: spy('flushQueuedMpvOsdNotifications', noop),
     refreshMpvSessionBindings: spy('refreshMpvSessionBindings', resolved),
     ensureImmersionTrackerStarted: spy('ensureImmersionTrackerStarted', noop),
@@ -212,7 +213,7 @@ test('createPlaybackAssembly does not call its deps while constructing', () => {
   assert.deepEqual(recorder.names(), []);
 });
 
-test('mpv connection starts the loading OSD and flushes queued OSD notifications before session work', () => {
+test('mpv connection starts the loading OSD, resends overlay readiness, and flushes queued OSD notifications before session work', () => {
   const { recorder, emit } = setup();
 
   emit('connection-change', { connected: true });
@@ -221,7 +222,11 @@ test('mpv connection starts the loading OSD and flushes queued OSD notifications
   const osdIndex = names.indexOf('maybeStartOverlayLoadingOsd');
   assert.ok(osdIndex >= 0);
   assert.deepEqual(recorder.calls[osdIndex]?.args, []);
-  assert.ok(osdIndex < names.indexOf('flushQueuedMpvOsdNotifications'));
+  assert.ok(osdIndex < names.indexOf('reportOverlayContentReadyToPlugin'));
+  assert.ok(
+    names.indexOf('reportOverlayContentReadyToPlugin') <
+      names.indexOf('flushQueuedMpvOsdNotifications'),
+  );
   assert.ok(
     names.indexOf('flushQueuedMpvOsdNotifications') < names.indexOf('refreshMpvSessionBindings'),
   );

src/main/assemblies/playback.ts

@@ -205,6 +205,7 @@ export interface PlaybackAssemblyDeps {
   ) => SubtitlePrefetchService;
   requestAppQuit: () => void;
   maybeStartOverlayLoadingOsd: OverlayNotificationsRuntime['maybeStartOverlayLoadingOsd'];
+  reportOverlayContentReadyToPlugin: OverlayNotificationsRuntime['reportOverlayContentReadyToPlugin'];
   flushQueuedMpvOsdNotifications: OverlayNotificationsRuntime['flushQueuedMpvOsdNotifications'];
   refreshMpvSessionBindings: () => Promise<void>;
   ensureImmersionTrackerStarted: () => void;
@@ -589,6 +590,7 @@ export function createPlaybackAssembly(deps: PlaybackAssemblyDeps) {
       },
       onMpvConnected: () => {
         deps.maybeStartOverlayLoadingOsd();
+        deps.reportOverlayContentReadyToPlugin();
         deps.flushQueuedMpvOsdNotifications();
         secondarySubtitleTrackController.scheduleRefresh(0);
         void deps.refreshMpvSessionBindings();