fix: allow test-action agent mode to run on claude bot PRs

The actor guard (github.actor != 'claude') was skipping test-agent-mode
on upstream-sync PRs. Refined the condition to only skip on non-PR events
(where tag mode loop risk exists) while allowing PR events through.

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

.forgejo/workflows/test-action.yml

@@ -23,7 +23,7 @@ jobs:
   test-agent-mode:
     name: Test Agent Mode on Forgejo
     runs-on: grunt
-    if: github.actor != 'claude'
+    if: github.actor != 'claude' || github.event_name == 'pull_request'
     steps:
     - name: Checkout
       uses: https://${{ secrets.READ_REPO_TOKEN }}@git.wxs.ro/xternal/checkout@v6.0.2