feat: IMAP mail sync with thread-to-contact matching (PRD §6.1)

Real IMAP connection via imapflow library:
- Connects to IMAP server (IMAPFlow, TLS on port 993)
- Fetches recent messages (configurable limit, default 20)
- Extracts: from, fromEmail, subject, date, snippet (200 chars)
- Thread-to-contact matching (PRD §6.1):
  1. Match sender email against persons table
  2. If no person match, extract domain and match against company.website
  3. Returns matchedCompany + matchedPerson for each email
- Audit-logged (action: crm.mailsync:imap)
- Zod validated (host, port, user, password, folder, limit)
- 502 on IMAP connection failure with detail
- 400 on validation failure

Tested: invalid creds → 502 'IMAP connection failed', missing host → 400

skills/quiz-mastery/skill.yaml

@@ -0,0 +1,21 @@
+name: quiz_mastery
+version: 0.2.0
+entrypoints:
+  run_quiz: scripts/run_quiz.py
+  submit_answers: scripts/submit_answers.py
+  generate_from_material: scripts/generate_from_material.py
+  import_quiz: scripts/import_quiz.py
+
+storage:
+  type: local_json
+  base_dir: ./data
+
+features:
+  - knowledge_extraction
+  - quiz_generation
+  - question_import
+  - answer_evaluation
+  - mastery_tracking
+  - weak_point_tracking
+  - ebbinghaus_review
+  - review_planning