docs(milestone): complete v0.2-ai-tutor-architecture

---ci---
phase: 7
milestone: v0.2
status: complete
requirements:
  covered: [REQ-2-001, REQ-2-002, REQ-2-003, REQ-2-004, REQ-2-005, REQ-2-006, REQ-2-007, REQ-2-008, REQ-2-009, REQ-2-010, REQ-2-011, REQ-2-012]
  partial: []
---/ci---

Milestone v0.2 (ai-tutor-architecture) merged to main.

Escalation record (audit remediation, durable): P1 executor
delegation failed twice (empty subagent results, zero files
created); auto-resolved at full autonomy to inline execution with
identical plan fidelity (commit 3271373, reflog-only after phase
branch squash-delete).

apps/ai-service/tests/test_health.py

@@ -0,0 +1,10 @@
+"""Health endpoint tests."""
+
+
+def test_health_returns_ok(client):
+    response = client.get("/health")
+    assert response.status_code == 200
+    data = response.json()
+    assert data["status"] == "ok"
+    assert data["provider"] == "mock"
+    assert data["model"] == "gemma4:31b"