Add editable and linked M3U playlists

[anilbeesetti]

Summary

• add a Playlists navigation destination with editable local playlists and linked M3U URL/file playlists
• support add-to-playlist from selected videos and folders, local playlist reordering, gear-based deletion, and linked playlist swipe-to-refresh
• parse large M3U sources with titles and artwork, preserve linked playlists as read-only, and propagate metadata into playback queues
• harden document grants, cancellation, repository validation, playback startup, thumbnail handling, and large-playlist processing

Verification

• full 707-task Gradle lint, unit-test, Android-test APK, and debug APK build gate passed
• 21 JVM test suites report zero failures or errors
• disposable emulator QA passed, including database and playlist instrumentation suites, and the created emulators were deleted
• feature installed successfully on the requested physical arm64 device

Notes

• Gradle project parallelism was disabled for the final gate invocation to avoid an Android APK packaging lock deadlock; no source workaround was required.