Add pull_request trigger for required workflow ruleset

Required workflows via rulesets need a pull_request trigger directly.
Falls back to org secret when not called via workflow_call.

.github/workflows/claude-code-review.yaml

@@ -1,6 +1,8 @@
 name: Claude Code Review
 
 on:
+  pull_request:
+    types: [opened, synchronize]
   workflow_call:
     secrets:
       anthropic_api_key:
@@ -22,7 +24,7 @@ jobs:
 
       - uses: anthropics/claude-code-action@v1
         with:
-          anthropic_api_key: ${{ secrets.anthropic_api_key }}
+          anthropic_api_key: ${{ secrets.anthropic_api_key || secrets.ANTHROPIC_API_KEY }}
           prompt: |
             Review this pull request. Focus on:
             - Code correctness and potential bugs