fix: add guardrail to upstream-sync prompt to prevent early stop

Claude was resolving merge conflicts but stopping before running tests,
committing, pushing, or creating the PR. Add explicit instruction that
the job is not done until the branch is pushed and PR is created.

.forgejo/workflows/upstream-sync.yml

@@ -331,6 +331,11 @@ jobs:
         prompt: |-
           You are automating an upstream sync for our Forgejo fork of anthropics/claude-code-action.
 
+          ## CRITICAL: Do NOT stop early
+          You MUST complete ALL steps below before stopping. Resolving conflicts alone is NOT sufficient.
+          Your job is NOT done until you have pushed the branch AND created (or updated) the PR.
+          If you stop before pushing and creating the PR, the entire sync fails.
+
           ## Current state
           - Branch: ${{ steps.prepare.outputs.branch }}
           - ${{ needs.check-upstream.outputs.behind }} commits behind upstream, ${{ needs.check-upstream.outputs.ahead }} commits ahead (our Forgejo changes)