Add Wear OS app: subscription and playback sync (phase 1)

[mapitman]

Summary

Build a standalone Wear OS module (wear/) that runs a companion podcast app on an LTE-capable watch, independent of the phone being nearby.

Since the target watch has LTE, phase 1 does not require moving downloaded audio files to the watch — episodes stream directly from enclosureUrl over the watch's own connection. That keeps this phase self-contained: no dependency on the download subsystem.

Scope

• New wear/ Gradle module sharing data/local entities/DAOs and data/repository with the phone app.
• Sync of subscriptions/queue (feed item metadata: title, enclosure URL, artwork, playback position) from phone to watch via the Wear OS Data Layer API (DataClient/MessageClient).
• A MediaSessionService on the watch module streaming directly from enclosureUrl (lighter than PlaybackController — no local-file-vs-stream branching needed since this phase streams only).
• Bidirectional playback-position sync so phone and watch stay in sync regardless of which device is playing.
• Minimal Wear Compose UI: queue list, now-playing/transport screen.

Out of scope (see follow-up issue)

Sending downloaded episode files to the watch for phone-free/off-LTE playback.

[mapitman]

Phase 1 is complete, across #278-#283:

• Extract data layer into a shared :core module (issue #276) #278: extracted the data layer into a shared :core module
• Add transport-agnostic Wear OS sync interface (issue #276) #279: transport-agnostic WearSyncClient sync interface
• Scaffold the :wear application module (issue #276) #280: scaffolded the standalone :wear Gradle module
• Wire up the phone/watch sync bridge (issue #276) #281: wired up the phone/watch sync bridge (queue + position, both directions)
• Add the watch's own playback service and controller (issue #276) #282: the watch's own playback service and controller
• Add the watch's queue and now-playing screens (issue #276) #283: the watch's queue and now-playing screens

Verified end-to-end on a Wear OS emulator: seeded a test episode into the watch's local (synced) database, launched the app, tapped the queued episode, confirmed navigation to the now-playing screen, confirmed real audio streamed and played over the watch's own connection, and confirmed auto-advance correctly emptied the queue once it finished.

Phase 2 (sending downloaded episodes to the watch for offline/no-network playback) is tracked separately in #277.