app: Scaffold Android TV PeerTube client (MVP)

Start the SmartTube-inspired PeerTube TV client as a Kotlin + Compose
for TV app. It targets any PeerTube instance (v1 API), with JTube as
the default, and covers login 0, local/own video listings 1-2, search
3, subscriptions 4, server-backed history 5 and HLS/progressive
playback with watching reports 6.

Password is only used for the OAuth password grant and never stored;
tokens are kept in EncryptedSharedPreferences. Building needs JDK 17+
(see README); the Gradle wrapper is checked in so no local Gradle is
required.

BACKLOG.md

@@ -0,0 +1,43 @@
+# Backlog
+
+Status vocabulary: `todo` · `doing` · `done`.
+
+## v0.1 — MVP (this release)
+
+| # | Item | Status | Notes |
+|---|------|--------|-------|
+| 0 | Ask for credentials + instance URL, store safely | todo | Login screen → `users/token`; store tokens + OAuth client creds in EncryptedSharedPreferences, never the password; refresh-token single-flight on 401 |
+| 1 | List local videos (public) + user's own videos incl. private/internal | todo | Sidebar entries "Videos" (public, `videos?isLocal=true`) and "My videos" (`users/me/videos`); privacy badge on non-public items |
+| 2 | List local channels | todo | `video-channels?search=&searchTarget=local`; tap → channel videos |
+| 3 | Search local videos | todo | `videos?search=…&isLocal=true` |
+| 4 | Subscription videos | todo | `users/me/subscriptions/videos` |
+| 5 | Watch history (server) | todo | `users/me/history/videos` read-only |
+| 6 | Playback + report to server history | todo | ExoPlayer HLS (mp4 fallback); `POST videos/{shortUuid}/watching` every ~20 s |
+
+## Next up (v0.2+)
+
+- Unified "accessible videos" feed: merge public-local + own private into one paged,
+  deduplicated list (v0.1 keeps them as two sidebar entries).
+- Logout / "switch account" button on the Home screen.
+- Playback polish: resume from server-recorded position, next/previous video from list,
+  auto-focus currently watched item on history screen.
+- Thumbnails of private/internal videos may 404 — probe server behavior and add a
+  fallback (generic poster) when required.
+- Verify `searchTarget=local` channel search behaves well for instances without
+  federation; consider `search/video-channels` endpoint as an alternative.
+- Release build: enable `minifyEnabled` + R8 rules, decide on signing, versioning scheme.
+- Error UX: friendlier messages (offline, instance down, wrong credentials vs. expired
+  token → re-login screen), retry buttons.
+- i18n: move user-facing strings to `strings.xml`, consider German + English.
+- Video detail screen (description, tags, views, duration, channel page link).
+
+## Longer term
+
+- Multiple saved instances / switching between them.
+- Live streams playback (HLS live), premieres.
+- Subtitles/captions selection.
+- Downloads for offline watching (probably limited to public videos).
+- Comments viewing (read-only) — needs moderation-safe UI thinking.
+- `BACKLOG` triage rhythm: keep "Next up" ≤ 8 items.
+- Out of scope by user request (do not implement without asking): uploading, editing,
+  subscribing/unsubscribing, deleting, creating channels/users/playlists.