Summary

• Port the OSS-safe upstream fixes from PixelPlayer after June 18: playlist edit serialization, conservative artist delimiters, album-artist persistence, lyrics glyph fallback, folder breadcrumb polish, and pause-on-volume-zero.
• Keep NetEase, Telegram, AI, Cast/Wear, and other non-OSS upstream changes out of this PR.
• Add focused regression coverage for artist delimiter migration/parsing, album display artist selection, and playlist concurrent removals.

Details

• Serializes playlist read-modify-write edits with a coroutine mutex so quick concurrent removals do not lose updates or leave playlist counts stale.
• Narrows default artist delimiters to ;, normalizes the old default delimiter set on read, and passes delimiter-aware artist parsing into album display artist selection.
• Persists edited album artist values through the local Room metadata update path.
• Adds a playback setting that pauses when system media volume reaches zero.
• Uses platform font fallback for lyrics text so extended Latin glyphs render reliably.
• Shows a home icon for the root folder breadcrumb state.

Validation

• JAVA_HOME=/usr/lib/jvm/java-21-openjdk PATH=/usr/lib/jvm/java-21-openjdk/bin:$PATH ./gradlew :app:compileDebugKotlin
• JAVA_HOME=/usr/lib/jvm/java-21-openjdk PATH=/usr/lib/jvm/java-21-openjdk/bin:$PATH ./gradlew :app:testDebugUnitTest --tests 'com.lostf1sh.pixelplayeross.data.worker.ArtistParsingUtilsTest' --tests 'com.lostf1sh.pixelplayeross.data.worker.AlbumGroupingUtilsTest' --tests 'com.lostf1sh.pixelplayeross.data.preferences.UserPreferencesRepositoryTest'
• JAVA_HOME=/usr/lib/jvm/java-21-openjdk PATH=/usr/lib/jvm/java-21-openjdk/bin:$PATH ./gradlew :app:compileDebugAndroidTestKotlin
• JAVA_HOME=/usr/lib/jvm/java-21-openjdk PATH=/usr/lib/jvm/java-21-openjdk/bin:$PATH ./gradlew :app:assembleRelease -Ppixelplayer.enableAbiSplits=false -Ppixelplayer.disableReleaseSigning=true

Notes

• The new playlist instrumentation test was compiled, but not run on a device/emulator in this pass.