ci: bound emulator smoke runtime

[papi-ux]

Summary

• Add a 35-minute job timeout for the emulator smoke job
• Add a 30-minute timeout around the emulator-runner step
• Set an explicit 15-minute emulator boot timeout and enable Gradle stacktraces for better failure logs

User-facing impact

• No app behavior changes.
• CI should fail clearly instead of hanging indefinitely when the emulator runner stalls.

Test plan

• Parsed .github/workflows/build.yml with Python YAML loader
• Ran git diff --check
• actionlint was not installed locally