feat: add formatted output for Claude Code execution reports (#18)

* feat: add formatted output for Claude Code execution reports

- Write turns formatter
- Modify GitHub Action to call formatter instead of dumping raw JSON
- Add comprehensive unit tests (30 tests) covering all functionality
- Add integration test with sample data for output consistency
- Support syntax highlighting for multiple content types (JSON, Python, bash, etc.)
- Include turn grouping logic and token usage tracking
- Provide CLI interface for standalone formatter usage

🤖 Generated with [Claude Code](https://claude.ai/code)
Note: seriously I have never written any line of ts code in my life, so
please make sure this is fine as I don't give any guarantees

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

* Add fallback

---------

Co-authored-by: Claude <noreply@anthropic.com>

action.yml

@@ -191,10 +191,18 @@ runs:
       if: steps.prepare.outputs.contains_trigger == 'true' && steps.claude-code.outputs.execution_file != ''
       shell: bash
       run: |
-        echo "## Claude Code Report" >> $GITHUB_STEP_SUMMARY
-        echo '```json' >> $GITHUB_STEP_SUMMARY
-        cat "${{ steps.claude-code.outputs.execution_file }}" >> $GITHUB_STEP_SUMMARY
-        echo '```' >> $GITHUB_STEP_SUMMARY
+        # Try to format the turns, but if it fails, dump the raw JSON
+        if bun run ${{ github.action_path }}/src/entrypoints/format-turns.ts "${{ steps.claude-code.outputs.execution_file }}" >> $GITHUB_STEP_SUMMARY 2>/dev/null; then
+          echo "Successfully formatted Claude Code report"
+        else
+          echo "## Claude Code Report (Raw Output)" >> $GITHUB_STEP_SUMMARY
+          echo "" >> $GITHUB_STEP_SUMMARY
+          echo "Failed to format output (please report). Here's the raw JSON:" >> $GITHUB_STEP_SUMMARY
+          echo "" >> $GITHUB_STEP_SUMMARY
+          echo '```json' >> $GITHUB_STEP_SUMMARY
+          cat "${{ steps.claude-code.outputs.execution_file }}" >> $GITHUB_STEP_SUMMARY
+          echo '```' >> $GITHUB_STEP_SUMMARY
+        fi
 
     - name: Revoke app token
       if: always() && inputs.github_token == ''