PUB-9: Refresh content after playback changes

[rovkinmax]

Task Summary

PUB-9 implements result-based auto-refresh for content mutations after returning from Player or nested Details flows.

• Adds a shared ContentChangeSet model and content-change result code.
• Makes AppRouter.navigateForResult stack-safe so nested Player/Details flows can share the same content-change result code.
• Propagates playback progress, watched, bookmark, and watchlist changes from Player/Details back to origin screens.
• Refreshes Details, Home, Favorites, Bookmarks, Content List, Show All, Search, and Collection Detail after relevant returned changes.
• Invalidates item-details and content-list caches so returned screens do not reload stale TTL data.
• Adds unit coverage for result routing, content-change merging, cache invalidation, and source-screen refresh behavior.

Compliance Review

Compliance Review: PASS. No direct compliance violations were found in the reviewed PUB-9 refactor/migration scope.

Verification

• ./tools/agentw :app:compileDevDebugKotlin - passed.
• ./tools/agentw :app:testDevDebugUnitTest - passed.

Skipped Checks

• Manual/emulator smoke was not run; it was not required without explicit smoke approval for this workflow step.