refactor: reorganize agent services into agent_coordination package and improve error handling

- Moved agent services to agent_coordination bounded context package:
  - agent_integration.py → agent_coordination/integration.py
  - agent_performance_service.py → agent_coordination/performance.py
  - agent_service.py → agent_coordination/agent_service.py
  - agent_security.py → agent_coordination/security.py
- Deleted agent_communication.py (988 lines removed)
- Updated import paths across routers to use new agent

dev/review/auto_review.py

@@ -58,7 +58,7 @@ def get_my_reviews(pr_number):
 
 # Stability ring definitions
 RING_PREFIXES = [
-    (0, ["packages/py/aitbc-core", "packages/py/aitbc-sdk"]),  # Ring 0: Core
+    (0, ["packages/py/aitbc-sdk"]),  # Ring 0: Core
     (1, ["apps/"]),                                           # Ring 1: Platform services
     (2, ["cli/", "analytics/", "tools/"]),                    # Ring 2: Application
 ]