fix(player): restore the subtitle sidecar work dropped by the previous commit

The previous commit was assembled from a tree read before 13264e22 landed,
so committing it reverted that commit's changes: the image-based subtitle
filtering in device_profile/types, subtitleTracks and its tests, the
regenerated bindings, and the VideoPlayer menu wiring.

Nothing was lost — the working tree held both changes throughout. This
restores those files to the merged state, leaving both the subtitle fix and
the play-session fix in place.

TRACES: UR-020, UR-004 | DR-176 | UT-168

src/lib/components/player/subtitleTracks.ts

@@ -32,6 +32,13 @@ export interface SubtitleStreamLike {
   displayTitle?: string | null;
   isDefault?: boolean;
   isForced?: boolean;
+  /**
+   * The backend's verdict on whether this track can arrive as a sidecar the app
+   * renders itself. `false` means only the server could have shown it, by
+   * burning it into the picture — which the app never asks for. Absent means no
+   * verdict was given, which is not the same as "no".
+   */
+  supportsExternalDelivery?: boolean | null;
 }
 
 /** A subtitle stream whose URL resolved — i.e. one we can actually render. */
@@ -46,12 +53,32 @@ export interface RenderableSubtitleTrack {
   isDefault: boolean;
 }
 
-/** Subtitle streams of a media item, in stream order. */
-export function subtitleStreamsOf(
-  streams: readonly SubtitleStreamLike[] | null | undefined,
-): SubtitleStreamLike[] {
+/**
+ * Subtitle streams of a media item that the app can actually show, in stream
+ * order. This is the one list behind everything: the picker, the `<track>`
+ * children, and the array sent to the native backend.
+ *
+ * Image-based subtitles (PGS/DVD/DVB) are filtered out here rather than at each
+ * consumer. They are bitmaps — a client can only display one if the server
+ * composites it into the video, and the app deliberately asks for no burn-in at
+ * all (DR-176), so such a track is one it can never draw. Leaving it in the
+ * picker produced a control that ticked and showed nothing.
+ *
+ * The judgement is the backend's: `supportsExternalDelivery` arrives already
+ * decided, because *which formats are bitmaps* is domain vocabulary and belongs
+ * in Rust. Only an explicit `false` drops a stream; a stream carrying no verdict
+ * is kept, so a source that never sets the field behaves exactly as before.
+ *
+ * Generic in the stream type so callers keep their own richer fields (the menu
+ * reads `codec` off the result).
+ *
+ * TRACES: UR-020 | DR-176 | UT-168
+ */
+export function subtitleStreamsOf<T extends SubtitleStreamLike>(
+  streams: readonly T[] | null | undefined,
+): T[] {
   if (!streams) return [];
-  return streams.filter((s) => s.kind === "subtitle");
+  return streams.filter((s) => s.kind === "subtitle" && s.supportsExternalDelivery !== false);
 }
 
 /** Human label for a subtitle stream, matching the menu's own fallback chain. */