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/api/bindings.ts

@@ -2235,7 +2235,20 @@ type: string;
 /**
  * Provider-neutral stream classification — replaces `stream_type`.
  */
-kind?: StreamKind; codec?: string | null; language?: string | null; displayTitle?: string | null; index: number; isDefault: boolean; isForced: boolean }
+kind?: StreamKind; codec?: string | null; language?: string | null; displayTitle?: string | null; index: number; isDefault: boolean; isForced: boolean; 
+/**
+ * Whether this stream can reach the app as a sidecar it renders itself.
+ * 
+ * `None` for anything that is not a subtitle — the question does not apply,
+ * and `false` there would read like a verdict. For a subtitle it is the
+ * difference between a track the app can draw and one only the server could
+ * have shown, by burning it into the picture (DR-176) — which this app never
+ * asks it to do. The vocabulary of *which formats those are* stays in Rust;
+ * the frontend only reads the answer.
+ * 
+ * TRACES: UR-020 | DR-176 | UT-168
+ */
+supportsExternalDelivery?: boolean | null }
 export type MediaType = "audio" | "video"
 /**
  * Lightweight media item for merged playback state