Fix container-build-and-release to resolve refs to full SHA

actions/checkout treats short SHAs as branch name patterns, causing
fetch failures. Always resolve --ref to a full 40-char SHA before
dispatching the workflow.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

mise-tasks/container-build-and-release

@@ -84,6 +84,9 @@ def main(
 
     if not ref:
         ref = git("rev-parse", "HEAD")
+    else:
+        # Resolve short SHAs or branch names to full SHA
+        ref = git("rev-parse", ref)
 
     short_sha = ref[:7]
     image = f"blumeops/{container}"