Add subprocess isolation setup and git credential helper (#1132)

- Add optional bubblewrap setup step for Linux subprocess isolation
  when allowed_non_write_users is configured
- Use git credential helper instead of embedding token in remote URL
- edit-issue-labels.sh: read issue number from workflow event payload
  instead of CLI arg
- Add CLAUDE_CODE_SCRIPT_CAPS env for per-script call limit config
- docs/security.md: note recommended github_token configuration

🏠 Remote-Dev: homespace

.github/workflows/issue-triage.yml

@@ -20,6 +20,8 @@ jobs:
 
       - name: Run Claude Code for Issue Triage
         uses: anthropics/claude-code-action@main
+        env:
+          CLAUDE_CODE_SCRIPT_CAPS: '{"edit-issue-labels.sh":2}'
         with:
           prompt: "/label-issue REPO: ${{ github.repository }} ISSUE_NUMBER: ${{ github.event.issue.number }}"
           anthropic_api_key: ${{ secrets.ANTHROPIC_API_KEY }}