W23: close mailroom metadata and network validation tests

- Refresh agents STATUS to W22.6 and exclude mailroom from metadata scans
- Add mailroom dispatch checklist and defensive rules
- Register F-23.D-1 and tag network input validation defense-in-depth
- Update network plugin tests for header length limits
- Fix LSP test metadata and remove orphan anthropic_internal.hpp

Verification:
- cmake --build build --config Release: 0 error, 0 warning
- ctest --test-dir build --output-on-failure: 10/10 passed
- ctest --test-dir build -R dstalk_smoke_test --output-on-failure: passed
- python scripts/check_agents_metadata.py --strict: passed

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

scripts/refresh_status.py

@@ -434,7 +434,7 @@ def main():
     # ---- Scan profiles ----
     profiles = []
     for child in sorted(agents_dir.iterdir()):
-        if not child.is_dir() or child.name.startswith('.') or child.name == 'groups':
+        if not child.is_dir() or child.name.startswith('.') or child.name in ('groups', 'audits', 'mailroom'):
             continue
         pf = child / 'profile.md'
         if pf.is_file():