Catch-up P1: launch past Guide programmes through service-owned playback intent

[MrFr3di]

Parent: #184
Follows: completed #285 / merged #304.

Objective

Complete the next M3U catch-up product slice: selecting a past EPG programme in Guide must start provider catch-up through the existing service-owned playback/recovery path, without constructing provider URLs in Guide/Compose and without introducing a second player, retry loop, or seek authority.

Confirmed current gap

• Guide programme cells currently call onOpenChannel(channelId) for every click, so past programmes collapse to ordinary Live playback.
• PlaybackCatalog.resolveIntent() and persisted M3U archive resolution are implemented, but PlaybackStartRequest is still Live/channel-only.
• MuxTvPlaybackService resolves candidates through PlaybackCandidateResolver.resolveCandidate(...), so resolving catch-up in presentation before the service would bypass the accepted bounded recovery owner.
• Guide presentation clips visible programme bounds to the viewport; catch-up must use the original EPG programme start/end, not clipped display bounds.

Architecture

• Keep PlaybackStartRequest provider-neutral and extend it with PlaybackIntent, while preserving the existing Live constructor/source compatibility.
• Preserve the existing service-owned candidate ordering/recovery. Add an intent-aware candidate-resolution seam with a Live default; RoomPlaybackCatalog resolves archive intent for the exact candidate selected by the service.
• Media3/session command transport serializes only semantic intent fields; no locator/template/token/header crosses this boundary.
• Guide emits only a provider-neutral selection: current/status -> Live, completed programme -> CatchupProgram, future programme -> no launch.
• App navigation stores only bounded semantic identities/timestamps and reconstructs PlaybackIntent at the player entry point.
• Playback: measured seek/rebuffer, back-buffer and optional cache residuals after single service-owned seek authority #132 remains the sole active seek mutation authority. No initial UI-owned seek is introduced.

TDD sequence

1. RED: PlaybackStartRequest + Media3 Bundle codec preserve CatchupProgram/CatchupPosition semantics and keep Live wire compatibility.
2. RED: service candidate resolution uses the exact selected candidate with archive intent and keeps bounded fallback.
3. RED: Guide selection uses original programme bounds, maps past/current/future correctly, and never constructs provider transport.
4. Minimal GREEN implementation.
5. Exact-head host validation plus canonical API26/API36/focused TV evidence appropriate to changed surfaces.

Acceptance

• clicking a completed Guide programme starts PlaybackIntent.CatchupProgram with original EPG start/end;
• current programme and non-programme/status cells preserve Live behavior;
• future programme does not start playback;
• service still owns candidate ordering, bounded fallback, generation cancellation and Media3 installation;
• archive-unavailable candidate can fall through to another eligible candidate under the existing recovery bounds;
• M3U/Kodi template syntax stays out of Guide, navigation and player:media3;
• no raw locator/query/token/Cookie/Authorization value enters navigation, Bundle diagnostics, UI semantics or logs;
• local-network and exact-origin cleartext gates still run on the final materialized archive locator;
• no Room migration;
• no second player/retry/seek owner;
• canonical persistent AVD set remains exactly API26 + API36.

Non-goals

Xtream catch-up, local timeshift, DVR, VOD/Series, new provider framework/module, new seek model, new persistent AVD, buffer tuning.

[MrFr3di]

TDD Task 1 RED captured on exact 19ad04d5b67552cfb8531b26667b2841b7cf22cb.

Hosted validation run 33582082379 / #2052 reached pure-kotlin-tests and failed specifically at :player:api:compileTestKotlin after production :player:api:compileKotlin succeeded. Expected diagnostics include Unresolved reference 'intent' and No parameter with name 'intent' in PlaybackStartRequestTest.kt.

This proves the missing provider-neutral semantic start-request contract. Proceeding with the minimum Task 1 GREEN only.