feat: add health check endpoint for agent authentication status

backend/tests/test_agent_health_api.py

@@ -0,0 +1,34 @@
+from __future__ import annotations
+
+from uuid import UUID, uuid4
+
+from app.api import agent as agent_api
+from app.core.agent_auth import AgentAuthContext
+from app.models.agents import Agent
+
+
+def _agent_ctx(*, board_id: UUID | None, status: str, is_board_lead: bool) -> AgentAuthContext:
+    return AgentAuthContext(
+        actor_type="agent",
+        agent=Agent(
+            id=uuid4(),
+            board_id=board_id,
+            gateway_id=uuid4(),
+            name="Health Probe Agent",
+            status=status,
+            is_board_lead=is_board_lead,
+        ),
+    )
+
+
+def test_agent_healthz_returns_authenticated_agent_context() -> None:
+    agent_ctx = _agent_ctx(board_id=uuid4(), status="online", is_board_lead=True)
+
+    response = agent_api.agent_healthz(agent_ctx=agent_ctx)
+
+    assert response.ok is True
+    assert response.agent_id == agent_ctx.agent.id
+    assert response.board_id == agent_ctx.agent.board_id
+    assert response.gateway_id == agent_ctx.agent.gateway_id
+    assert response.status == "online"
+    assert response.is_board_lead is True