feat(channels): add Manage Channels TV surface

[MrFr3di]

Scope

Stacked on #245. Implements CC-3: a dedicated TV Manage Channels surface backed by the hidden-aware management projection and profile-scoped channel preference mutations.

• entry point from the Channels screen;
• All / Visible / Hidden management filters;
• show canonical vs effective name/number and hidden/favorite state;
• hide/unhide, rename, custom number and reset presentation actions;
• hidden channels remain recoverable only through management;
• normal Channels browse semantics remain unchanged;
• no Room schema change and no provider/player ownership changes.

Implementation is RED-first and remains draft until exact-head hosted + TV/device checks are green.

[MrFr3di]

2026-09-01 restack analysis: canonical CC-3 incremental diff vs #245 is 8 files. Seven can be carried as-is; the only external-main overlap is app/tv/src/main/kotlin/app/muxtv/navigation/AppNavigation.kt, which changed during the Android17 train. Rebuild CC-3 after #245 with a semantic union only for AppNavigation, preserving both Android17 permission routing and Manage Channels navigation. Duplicates #247/#253 are closed.