The custom-provisioned preview job hung in 'Boot emulator and run E2E' until
the 35-min cap: adb wait-for-device had no timeout and the emulator's own
output was never captured, so a failed boot was both invisible and unbounded.
Bound the wait with a single 300s timeout covering device registration + full
boot, retry once, capture the emulator log, and dump it (plus logcat) on
failure.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>