home: Title bar with account and channel pages

The header-removal experiment went too far: the app now has a slim
persistent title bar — logo + "JTube TV" on the left (it anchors the
layout while the drawer is open), avatar + display name on the right as
a purely visual indicator so it never steals D-pad focus. LEFT from the
first card of every row opens the drawer (the subscriptions row silently
skipped it, and the grid only wired the very first item), and UP no
longer surprises by opening anything.

The channel page that the Channels screen and the player's channel icon
point at never actually rendered — ListSource.Channel, its repository
call and the header state all existed without a UI. Videos of one
channel now open as a grid with banner, avatar, name and handle; page
headers (search field, channel banner) live inside the grid so they
scroll along instead of stacking under the cards.

Closes #7

BACKLOG.md

@@ -13,6 +13,14 @@ Status vocabulary: `todo` · `doing` · `done`.
 | 4 | Subscription videos | done | Verified incl. remote (federated) channels |
 | 5 | Watch history (server) | done | read-only grid |
 | 6 | Playback + report to server history | done | ExoPlayer HLS w/ `videoFileToken` for non-public media; watching reports every ~20 s verified server-side; resume position retrievable |
+| 7 | Channel videos view (channel page) | done | Banner + avatar + name + video count header, paged video grid; opened from the Channels screen and the player's channel icon |
+
+## Discussed but deferred (2026-10-12, while reworking the player controls)
+
+- Like/dislike display: counts are in the video detail DTO; rating (own like via
+  `PUT /api/v1/videos/{uuid}/rating`) is a write op — display first, rating later.
+- Subtitles: `GET /api/v1/videos/{uuid}/captions` → Media3 `SubtitleConfiguration`
+  on the player; language selection in the controls overlay.
 
 ## Next up (v0.2+)