fix(ci): set mode to agent for automatic execution

The beta version defaults to 'tag' mode which requires manual triggering.
Set mode to 'agent' to run automatically on PR events.

.github/workflows/claude-link-review.yml

@@ -25,6 +25,7 @@ jobs:
       - name: Run Claude Link Review
         uses: anthropics/claude-code-action@beta
         with:
+          mode: agent
           use_sticky_comment: true
           anthropic_api_key: ${{ secrets.ANTHROPIC_API_KEY }}
           github_token: ${{ secrets.GITHUB_TOKEN }}

.github/workflows/claude-model-check.yml

@@ -24,6 +24,7 @@ jobs:
       - name: Claude Model Validation
         uses: anthropics/claude-code-action@beta
         with:
+          mode: agent
           use_sticky_comment: true
           anthropic_api_key: ${{ secrets.ANTHROPIC_API_KEY }}
           github_token: ${{ secrets.GITHUB_TOKEN }}

.github/workflows/claude-notebook-review.yml

@@ -25,6 +25,7 @@ jobs:
       - name: Run Claude Notebook Review
         uses: anthropics/claude-code-action@beta
         with:
+          mode: agent
           use_sticky_comment: true
           anthropic_api_key: ${{ secrets.ANTHROPIC_API_KEY }}
           github_token: ${{ secrets.GITHUB_TOKEN }}