feat(auth): bootstrap android dashboard token

[TimeToBuildBob]

Summary

• bump the embedded aw-server-rust submodule to the Android auth-capable commit from fix(android): load embedded server config aw-server-rust#608
• ensure Android writes a non-empty [auth].api_key into filesDir/config.toml before starting the embedded server
• append ?token=... to the embedded WebView URL and add a real Open in browser action for the external browser path
• add JVM unit tests for token URL building plus auth-config extraction/upsert behavior

Why

This is the app-side slice of #145 now that the server-side Android config prerequisite merged in ActivityWatch/aw-server-rust#608.

Testing

• git diff --check
• Local Gradle/unit-test execution is still blocked in the current container because there is no Java/Android SDK toolchain here
• GitHub Actions on this draft PR should exercise the Android build/test matrix

[TimeToBuildBob]

CI note: the first failed check is Get latest versionCode, but it failed in Load Fastlane secrets before touching this patch. That looks like the repo's secret-gated Fastlane lane on a fork PR, not an auth-regression signal from this branch.

The more relevant lane for this change is Build aw-server-rust, which is still running.

[TimeToBuildBob]

Rebased onto master to pick up the ubuntu-20.04 → ubuntu-22.04 runner fix (#163). The previous E2E failure at 'Set up job' was caused by the deprecated ubuntu-20.04 runner, not a code issue. Triggering a fresh CI run.