[A-EDev]

Summary

• Linked-devices state belongs to the device: the linked_store folder moves to device scope (Default's path is unchanged) and the inventory marks it and linked_devices as DEVICE.
• The linked sync, the LAN service, the live socket and the sync worker run in every profile. Outside Default a run keeps the group up to date (roster, rotation, uploads, garbage collection, join requests) but sends and applies nothing, since only Default is linked until profiles choose their links.
• Now playing names no link outside Default.
• A profile switch waits while a linked sync runs, as it already did for one-time sync.

Related issue

Part of #1039 (Phase 6 of FLOW-SYNC/2).

Change type

• Bug fix
• Feature
• Refactor or maintenance
• Build, packaging, or CI
• Documentation

Validation

All Gradle runs used --offline -Dorg.gradle.jvmargs="-Xmx4096m -XX:MaxMetaspaceSize=1024m -Dfile.encoding=UTF-8 -Djava.net.preferIPv6Addresses=true".

• ./gradlew :app:assembleGithubDebug: not run on this branch; the top of the stack builds it.
• ./gradlew :app:testGithubDebugUnitTest: 4721 tests, 0 failures, 46 skipped.
• I ran any additional flavor-specific build or test tasks affected by this change: testFossDebugUnitTest 4678 tests, 0 failures, 46 skipped; ktlintCheck, spotlessCheck and lintGithubRelease pass; assembleFossRelease builds, FOSS arm64-v8a APK 21,803,740 B (budget 29,500,000 B).
• I manually tested the affected behavior on an Android device or emulator.

Test device and Android version:

Risk and compatibility

No schema change. Storage paths are unchanged for Default; another profile now reads the device's linked_store instead of an unused private copy.

• The change does not introduce secrets, private data, or unexpected telemetry.
• New user-facing text uses Android string resources.
• Dependency and lockfile changes are intentional and limited to this PR.
• Room schema changes include the required version bump and migration, or this PR does not change the Room schema.
• Breaking changes and upgrade steps are clearly documented.