ci: run the release smoke test weekly

Add a Monday 06:00 UTC schedule. Scheduled runs carry no input, so the
resolve job auto-picks the latest Maven Central release — catching Central
or runner-image drift against the published artifact without a manual run.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

Author: dfa1

.github/workflows/release-smoke.yml

@@ -12,6 +12,11 @@ on:
         description: Version to smoke-test. Leave blank to use the latest release on Maven Central.
         required: false
         default: ""
+  schedule:
+    # Weekly, Mondays 06:00 UTC. No input on scheduled runs, so the resolve job
+    # picks the latest release on Maven Central — catches Central / runner-image
+    # drift against the published release without a manual trigger.
+    - cron: "0 6 * * 1"
 
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