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).

.gitignore

@@ -42,4 +42,9 @@ yarn-error.log*
 
 # Test coverage
 coverage/
-.nyc_output/
+.nyc_output/
+
+# Python tooling caches
+.pytest_cache/
+.ruff_cache/
+*.egg-info/