[A-EDev]

Summary

An edit made right after a sync could lose to the very change it followed: last-writer-wins compares stamps, and this device stamped its edit with its own wall clock, which may be behind the other device's. Flow-Tube/flow-sync#38 now says what "hybrid logical clocks are persisted" means, and this implements it:

• DeviceIdentity keeps the highest physical time of any stamp this device has applied (clock_ms in the existing sync_identity store).
• editTime() returns max(now, that + 1).
• SyncChangeTracker stamps every local edit and tombstone with editTime(), and raises the mark whenever a merge settles.

The wire format doesn't change. This covers FLOW-SYNC/1 sessions and the coming linked-devices sync alike.

Related issue

Part of #1075 (linked devices).

Change type

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

Validation

• ./gradlew :app:assembleGithubDebug: ok (on top of fix(sync): let sync remove a channel from a group #1543, which includes this commit)
• ./gradlew :app:testGithubDebugUnitTest: 4570 passed, 46 skipped, 0 failed (same); new SyncChangeTrackerTest.an_edit_after_a_newer_peer_stamp_is_stamped_after_it
• ./gradlew ktlintCheck: ok
• I manually tested the affected behavior on an Android device or emulator. (Not run on a device; covered by unit tests.)

Test device and Android version: none (JVM tests)

Risk and compatibility

One new key in the existing device-only sync_identity DataStore. Flow Desktop ships the same rule in its own PR.

• The change does not introduce secrets, private data, or unexpected telemetry.
• New user-facing text uses Android string resources. (None.)
• Dependency and lockfile changes are intentional and limited to this PR. (None.)
• 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. (None.)