Bootstrap Castarr from NodeCast prototype

Imported the native TV app (Kotlin, ExoPlayer, embedded remote server, QR
pairing) plus CONTEXT.md and ADRs 0001-0005. Rename, Compose for TV UI and
the Dispatcharr integration follow as tracked issues.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

README.md

@@ -0,0 +1,21 @@
+# Castarr
+
+Native Google TV client for a [Dispatcharr](https://github.com/be-nj/Dispatcharr)
+backend: live IPTV with a full D-pad UI, login via OIDC device flow
+(Authentik), per-user favorites, and an optional phone remote paired by QR
+code (served by the TV itself, no phone app install).
+
+Status: bootstrap. The code base was imported from the NodeCast prototype
+(phone-remote-first, M3U standalone) and is being reshaped per the decisions
+in [CONTEXT.md](CONTEXT.md) and [docs/adr/](docs/adr/) — see the issue tracker
+for the phase-1 slices.
+
+## Building
+
+Requires JDK 17+ and the Android SDK (platform 35).
+
+```
+./gradlew assembleDebug
+```
+
+APK output: `app/build/outputs/apk/debug/app-debug.apk`.