Review triggers were lost when the user left the screen immediately

[mpretty-cyro]

A review trigger emitted from a screen the user immediately leaves never arrives, so the prompt never shows.

What happens

Change the theme in Appearance and press back, and no review prompt appears — not late, never. Found by Review prompt Appearance trigger in the Appium suite, which had never passed.

Why

InAppReviewManager's event channel was a rendezvous channel (capacity 0). On a rendezvous channel send does not complete when it is called — it suspends until the collector receives. Every call site wrapped it in the screen's own scope:

PathActivity.kt:114              lifecycleScope.launch
SettingsViewModel.kt:642         viewModelScope.launch      <- Donate
AppearanceSettingsViewModel:33   viewModelScope.launch      <- setNewAccent
AppearanceSettingsViewModel:45   viewModelScope.launch      <- setNewStyle

So the emission had to outlive the screen that triggered it. Changing a theme is the one interaction a user reliably follows with "back" within milliseconds, which is why Theme lost it and Path and Donate did not — all four were equally exposed; three survived on user behaviour rather than on structure. A fast enough Donate tap has the same defect.

The change

The channel becomes UNLIMITED and onEvent becomes non-suspending (trySend), so no caller needs a coroutine and the four call sites reduce to a plain call. Fixing AppearanceSettingsViewModel alone would have left Donate and Path racing and looked fixed, because those two are hard to lose by hand.

A dropped trySend is logged rather than swallowed. On an unlimited channel it is unreachable short of the manager being closed, but silence there would look exactly like the bug this replaces.

setNewAccent is covered by the same change; it had the identical shape and no coverage.

Verification

Two new tests in InAppReviewManagerEventDeliveryTest. The first fires an event before the collector has started — the precise moment a rendezvous channel had nowhere to put it — and waits with first { it } rather than sampling, so a lost event fails by timing out instead of by reading a stale false.

Mutated by setting the capacity back to RENDEZVOUS while keeping trySend: both tests fail. That isolates the buffer as the thing doing the work rather than the non-suspending signature.

End to end: all six Review prompt * Appium specs pass against this build, including Appearance trigger, which was previously unreachable rather than flaky.

Note

Touches InAppReviewManagerTest.kt, which qa/review-prompt-app-updated-extra also adds a class to — the two conflict on that file and want stacking or a merge order.