What changed

Fixed a bug where the app would silently stop updating AirPods data (battery levels, in-ear status, case-open popup, widgets) on some Android 10 and 11 devices. Once the bug triggered, every screen and widget would freeze on the last value seen until the app was force-quit.

Also rolled into the same fix:

• DeviceInfo updates (firmware version, marketing version, per-earbud serials) are now persisted even when no fresh battery reading is available.
• Persistence errors can no longer silently freeze the data flow — failures are caught, logged, and reported once per device.

Technical Context

• Root cause: existing.percent == livePercent in mergeBatterySlot compiled to Intrinsics.areEqual(Float, Float) because livePercent: Float? retains JVM type java.lang.Float even after the smart cast. R8 inlined areEqual and dropped the second-operand null check on Android 10/11's interpreter+JIT path, NPE'ing inside the supposedly null-safe helper.
• The throw escaped through liveState.onEach { persistLiveDevices(...) }, cancelling the upstream combine. replayingShare's WhileSubscribed(Duration.ZERO) then re-ran the deterministic crash on every restart, so observers were left stuck on the cached replay=1 value.
• Fix: mergeBatterySlot now Elvis-unboxes Float? to primitive float; slot percent comparisons in hasStateChanged are routed through a new hasSlotChanged helper that compares primitive float directly. Verified at the dex bytecode level via apkanalyzer: both methods emit cmpg-float with no Intrinsics.areEqual invocation in the merge path.
• hasStateChanged also now compares leftEarbudSerial / rightEarbudSerial / marketingVersion (added in #32ff7e5b but never wired into dedup), and toCachedState no longer skips when only DeviceInfo is fresh. To make that path actually fire, liveState.onEach now also persists AAP-only profiles (active AAP, no BLE in this scan).
• The new try/catch in persistLiveDevices is defense-in-depth: any future merge-path bug logs and reports once per profileId instead of cancelling the upstream flow.

Review checklist

• mergeBatterySlot and hasSlotChanged show cmpg-float and no Intrinsics.areEqual in the dex bytecode of assembleFossRelease
• AAP-only persistence in liveState.onEach doesn't double-write or feedback-loop against the existing nonLiveDevices synthesis in the devices flow
• reportedPersistFailures dedup is acceptable as a process-lifetime per-profile suppression