.git-commit-msg

feat: implement A2A agent-to-agent communication system

Adds complete A2A communication infrastructure:

Go CRD and Controller:
- AgentCard CRD for agent discovery with skills, endpoint, auth, health check
- AgentCard controller with health probing and status reconciliation
- A2A fields on AgentWorkload: collaborationMode, agentRefs, per-agent status
- Full DeepCopy support for all new types
- AgentCard CRD manifest with printer columns and validation
- Registered AgentCardReconciler in operator main.go

Python A2A SDK (agents/a2a/):
- protocol.py: Pydantic v2 models (Task, TaskResult, AgentMessage, TaskStatus)
- store.py: PostgreSQL-backed task store with connection pooling
- server.py: FastAPI A2A server (agent-card, tasks CRUD, health)
- client.py: A2A client with K8s agent discovery

Supporting files:
- Architecture doc (docs/a2a-architecture.md)
- Sample manifests (config/samples/a2a_team_example.yaml)
- E2E test script (tests/e2e/test_a2a.sh)

All Go tests pass. Zero SQL injection vectors (parameterized queries only).