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.

README.md

@@ -0,0 +1,69 @@
+# JTube TV
+
+An Android TV client for [PeerTube](https://joinpeertube.org/) instances, inspired by
+how SmartTube works for YouTube. It talks to **any PeerTube instance**
+(the default is [JTube](https://tube.jeena.net) — my own instance) over the
+[PeerTube REST API](https://docs.joinpeertube.org/api-rest-reference.html).
+
+## Features (v0.1)
+
+- **Setup flow** — enter instance URL, username and password once; the app exchanges
+  them for OAuth tokens via `POST /api/v1/users/token` and stores
+  **only the tokens** (never the password), encrypted with the Android Keystore
+  (EncryptedSharedPreferences).
+- **Local videos** — list public videos of the instance (`GET /api/v1/videos?isLocal=true`).
+- **My videos** — all of the logged-in user's own videos, every privacy level included
+  (private, internal, unlisted — `GET /api/v1/users/me/videos`). Non-public entries
+  carry a privacy badge.
+- **Channels** — list channels local to the instance
+  (`GET /api/v1/video-channels?search=…&searchTarget=local`) and browse each channel's videos.
+- **Search** — search local videos by title.
+- **Subscriptions** — the videos in the user's subscription feed
+  (`GET /api/v1/users/me/subscriptions/videos`).
+- **History** — the user's watch history as tracked by the server
+  (`GET /api/v1/users/me/history/videos`).
+- **Playback** — HLS (or progressive MP4 fallback) playback with ExoPlayer/Media3.
+  Viewing is reported to the server (`POST /api/v1/videos/{shortUuid}/watching`) so it
+  shows up in server-side history. Private/internal media is streamed with the OAuth
+  token attached to every playlist/segment request.
+
+Out of scope for now (see `BACKLOG.md`): uploading, editing, subscribing/unsubscribing,
+deleting, creating anything other than history entries.
+
+## Build
+
+Requirements: JDK 17+ (JDK 21 recommended), Android SDK platform 35.
+`local.properties` with `sdk.dir=…` is picked up automatically if present
+(standard Android Gradle Plugin behavior).
+
+```bash
+./gradlew :app:assembleDebug
+```
+
+Install on a TV device:
+
+```bash
+adb connect <tv-ip>:<port>
+adb install -r app/build/outputs/apk/debug/app-debug.apk
+```
+
+> Building requires a JDK; the Gradle wrapper is checked in, so no local Gradle
+> installation is needed.
+
+## Architecture overview
+
+Single-module Android TV app (`app/`):
+
+- `data/api` — Retrofit interface + kotlinx-serialization DTOs for the PeerTube API.
+- `data/auth` — `TokenStore` (EncryptedSharedPreferences), token acquisition/refresh.
+- `data/network` — OkHttp/Retrofit wiring: dynamic base-URL interceptor, bearer-token
+  interceptor, single-flight token refresh authenticator.
+- `data/PeerTubeRepository.kt` — one suspend-call surface used by all view models.
+- `ui/` — Compose for TV screens: Setup, Home (sidebar + list content),
+  VideoList (local / my videos / subscriptions / history / search / channel),
+  Channels, Player. `MainActivity` is the only activity.
+- `JTubeApp.kt` — tiny service locator (`AppGraph`); no DI framework on purpose.
+
+## License
+
+Not decided yet — TBD before first public release.