fix: persist and recover the Agent's real installation_id (heartbeat activation)

POST /v1/agents/enroll now returns installation_id; new installs persist it
to agent.env immediately. Runtime recovery precedence: existing SQLite
installation_identity -> configured INSTALLATION_ID -> authenticated
GET /v1/agents/me/identity. Recovery fails closed on missing/malformed/
mismatched identity rather than inventing a UUID (which the Hub would then
reject as a conflicting Installation on an already-enrolled Agent). An
explicit AGENT_JOBS_ENABLED gate stops the service from claiming a job right
after the first heartbeat.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

central/tests/test_install_code_enrollment.py

@@ -128,6 +128,7 @@ def test_enroll_with_install_code_alone_creates_agent(hub, release_id):
     assert enrolled.status_code == 200
     body = enrolled.json()
     assert body["agent_id"] and body["agent_token"] and body["hostname_mismatch"] is False
+    assert body["installation_id"] == uuid
 
     with factory() as session:
         agent = session.get(Agent, body["agent_id"])
@@ -416,4 +417,4 @@ def test_revoke_clears_code_and_is_audited(hub, tmp_path):
         enr = session.scalar(select(AgentEnrollment).where(AgentEnrollment.enrollment_uuid == installation_uuid))
         assert enr.status == "REVOKED" and enr.install_code_hash is None
     events = {e.action for e in audits(factory)}
-    assert "INSTALLATION_CODE_CREATED" in events and "INSTALLATION_CODE_REVOKED" in events and "INSTALLATION_REVOKED" in events
+    assert "INSTALLATION_CODE_CREATED" in events and "INSTALLATION_CODE_REVOKED" in events and "INSTALLATION_REVOKED" in events

central/tests/test_jobs.py

@@ -5,7 +5,7 @@ from sqlalchemy.pool import StaticPool
 
 from central.app.jobs import claim_next_job, complete_job, create_job, fail_job
 from central.app.main import create_app
-from central.app.models import Agent, Base, BlockedProduct, Job, Tenant
+from central.app.models import Agent, Base, BlockedProduct, Installation, Job, Tenant
 
 
 def _make_agent(session):
@@ -118,6 +118,63 @@ def test_agent_status_derives_online_offline():
     assert "company_id" in body
 
 
+def test_agent_identity_endpoint_returns_existing_installation_identity_only():
+    client, _ = _client()
+    headers = {"Authorization": "Bearer test-token"}
+    installation_id = "00000000-0000-4000-8000-000000000222"
+
+    heartbeat = client.post(
+        "/v1/agents/heartbeat",
+        json={
+            "installation_id": installation_id,
+            "hostname": "DESKTOP-B0HL02I",
+            "agent_version": "1.1.1",
+            "status": "IDLE",
+        },
+        headers=headers,
+    )
+    assert heartbeat.status_code == 200
+
+    response = client.get("/v1/agents/me/identity", headers=headers)
+
+    assert response.status_code == 200
+    assert response.json() == {
+        "agent_id": heartbeat.json()["agent_id"],
+        "installation_id": installation_id,
+        "hostname": "DESKTOP-B0HL02I",
+        "version": "1.1.1",
+        "status": "ONLINE",
+    }
+
+
+def test_agent_identity_endpoint_returns_null_installation_without_creating_one():
+    client, engine = _client()
+    headers = {"Authorization": "Bearer test-token"}
+
+    response = client.get("/v1/agents/me/identity", headers=headers)
+
+    assert response.status_code == 200
+    body = response.json()
+    assert body == {
+        "agent_id": body["agent_id"],
+        "installation_id": None,
+        "hostname": None,
+        "version": None,
+        "status": "OFFLINE",
+    }
+    assert isinstance(body["agent_id"], int) and body["agent_id"] > 0
+    with Session(engine) as session:
+        assert session.query(Installation).count() == 0
+
+
+def test_agent_identity_endpoint_requires_agent_authentication():
+    client, _ = _client()
+
+    response = client.get("/v1/agents/me/identity")
+
+    assert response.status_code == 401
+
+
 def test_job_creation_rejects_unknown_kind():
     client, _ = _client()
     headers = {"Authorization": "Bearer test-token"}