fix(android): make onInit resilient to slow/broken TTS engines (ANR + OOM)

[ninjz]

Related to #11 / #12: this keeps initLock off the TextToSpeech call path, so it doesn't reintroduce that ABBA deadlock. It fixes a different pair of crashes (a main-thread-enumeration ANR and a getVoices() OOM), so it's complementary — happy to rebase onto #12 if that lands first.

Problem

Two crashes on low-end Android share one root cause — the onInit SUCCESS branch enumerates voices/engines synchronously on the main thread:

1. ANR — main thread stuck executing synthesizer.voices / synthesizer.engines (not lock-waiting; distinct from Android ANR/deadlock: ensureInitialized holds initLock while calling TextToSpeech APIs #11's deadlock). Observed on a 4 GB, Android 15 device.
2. OOM crash — uncaught OutOfMemoryError from TextToSpeech.getVoices() on some cheap engines (seen on MediaTek/UMIDIGI Android 12).

Root cause

Android delivers the TextToSpeech OnInitListener on the main thread (SetupConnectionAsyncTask.onPostExecute). The SUCCESS branch then runs, synchronously on that thread:

• synthesizer.engines
• applyGlobalOptions() → synthesizer.voices (when a voice is configured)
• processPendingOperations(), which drains queued getAvailableVoices / getEngines / configure

These are synchronous Binder IPC round-trips to the engine process.

• ANR: on a cold engine under memory pressure these take seconds; back-to-back on the UI thread they cross the 5 s ANR threshold.
• OOM: setLanguage() / voices both hit getVoices(). Some engines return a pathological serialized Voice[] that OutOfMemoryErrors while deserializing — a runaway allocation, not memory pressure (seen with ~2.9 GB free). The existing catch (e: Exception) doesn't catch it (OOM is an Error, not an Exception), so it escaped uncaught and crashed the app.

Fix

• Off the main thread. Run the enumeration + global-config + queue drain on a background thread. Config is applied before isInitialized flips, so a caller can't speak before config is applied. initLock guards only the flag flip — applyGlobalOptions() and the drain run lock-free, because holding initLock across a TextToSpeech call is the ABBA deadlock from Android ANR/deadlock: ensureInitialized holds initLock while calling TextToSpeech APIs #11. cachedEngines becomes @Volatile.
• Catch the OOM. Widen catch (e: Exception) → catch (e: Throwable) in applyGlobalOptions() and applyOptions() (the two getVoices()-triggering methods), and backstop the background thread with try/catch (Throwable) — an uncaught throwable on a raw Thread still kills the app.
• Also resolve synthesizer.defaultEngine once in getEngines() instead of once per engine in the loop (one Binder IPC instead of N).

Testing

• :compileReleaseKotlin → BUILD SUCCESSFUL.
• The OOM guard is native Kotlin, not reachable from a JS test suite — it's validated by compileReleaseKotlin plus the reasoning above (OOM is a Throwable but not an Exception; widening the catch + the thread backstop close the uncaught path). I can't deterministically reproduce either crash (both sampled and device-specific), but the change removes all synchronous cross-process IPC from the UI thread, applies config before opening the barrier, keeps initLock off the TTS call path, and converts a getVoices() OOM from an app kill into a silent degrade.