fix(watcher): resume unlock ingest from the unlock bucket's last event

[0xbrayo]

Part of #333.

SessionEventWatcher used the start of the last stored session as the lower bound for both the session query and the unlock (KEYGUARD_HIDDEN) query. Every run therefore re-sent every unlock since that session started.

Unlocks are sent as heartbeats with pulsetime = 0. The server only merges a heartbeat into the newest event in the bucket, and refuses to merge one older than it, so on each run only the newest unlock merged and every older one in the window was inserted again. Runs happen hourly, on every app open and on widget refresh, so unlock counts kept inflating.

Change

• getLastEventTime() takes the bucket id.
• Unlocks resume from 1 ms after the last event in aw-watcher-android-unlock; sessions keep their own cursor.

A fresh unlock bucket still starts from 0, which is correct because nothing has been stored there yet.

Testing

• ./gradlew :mobile:testStandardDebugUnitTest passes.
• The changed code is in SessionEventWatcher, which needs a live RustInterface and UsageStatsManager, so this has no new unit test.

Tested on an emulator

Setup: arm64 emulator (API 37, 16 KB pages), debug builds of both versions.

• Baseline: upstream master (26fdffa) with aw-server-rust 70ba50d.
• Fixed: test/all-fixes, all of Correctness and performance issues in watchers, sync and workers #333's PRs combined, so this fix is not exercised in isolation.

Data was read back through the app's REST API, and imports were triggered with the app's exported LOG_DATA alarm action while another app stayed in front.

The test enabled the swipe lock screen, then did 5 lock/unlock cycles with Settings in front. Each unlock was kept under a second, so no session was recorded between them. It then ran 4 imports. Android's own usage stats confirmed the KEYGUARD_HIDDEN events.

	Unlocks performed	Unlock events stored	Distinct timestamps	Duplicates
Baseline	5	11	5	6
Fixed	5	5	5	0

[greptile-apps]

Confidence Score: 5/5

[Medium impact] The PR appears safe to merge; no new actionable issues were found.

Summary

The PR gives unlock collection its own stored-event cursor.

• Unlock imports resume after their own latest stored event.

_{Reviews (3) · Last reviewed commit: "fix(watcher): resume unlock ingest from ..." · Reviewed by Greptile}

[0xbrayo]

🤖 Claude, on behalf of @0xbrayo

@greptile review

[0xbrayo]

🤖 Claude, on behalf of @0xbrayo

@greptile review