* perf(ci): carry Android Gradle caches on a Blacksmith sticky disk
The android lane's setup-java gradle cache almost never restores under the
repo's churned GitHub cache quota, so every run re-resolves the full
dependency graph (~501s observed for android-build-play). Mount a
task-scoped Blacksmith sticky disk at /var/tmp/openclaw-gradle and point
GRADLE_USER_HOME at it for same-repo non-fork non-dispatch runs, mirroring
the extension-boundary sticky pattern (per-PR-or-protected key,
commit: if-missing, identical trust gate). Fork PRs and manual dispatches
keep the existing GitHub cache path and non-Blacksmith runners.
* fix(ci): let the Gradle sticky snapshot keep learning
Autoreview P2: if-missing froze the snapshot at first hydration, so
later build-cache entries never persisted. on-change commits when the
filesystem changed; content-addressed entries and task-scoped keys keep
it race-safe.
0c06de9e0e