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/src/quiz_mastery/evaluator.py

@@ -0,0 +1,78 @@
+from __future__ import annotations
+
+from .models import Question, AnswerResult
+
+
+class Evaluator:
+    """Evaluates user answers against correct answers.
+
+    - single_choice / true_false: exact match
+    - fill_blank: case-insensitive, strip whitespace
+    - short_answer: no auto-scoring, returns needs_review=True
+    """
+
+    def evaluate_answers(
+        self,
+        questions: list[Question],
+        user_answers: dict[str, str],
+    ) -> list[AnswerResult]:
+        results: list[AnswerResult] = []
+
+        for q in questions:
+            user_answer = user_answers.get(q.id)
+
+            if q.type == "short_answer":
+                # Short answer: cannot auto-evaluate, needs human/LLM review
+                results.append(
+                    AnswerResult(
+                        question_id=q.id,
+                        user_answer=user_answer,
+                        is_correct=None,
+                        score=None,
+                        feedback="需要人工/LLM评判",
+                        error_type="pending_review",
+                        needs_review=True,
+                    )
+                )
+                continue
+
+            if user_answer is None:
+                results.append(
+                    AnswerResult(
+                        question_id=q.id,
+                        user_answer=None,
+                        is_correct=False,
+                        score=0.0,
+                        feedback=f"未作答。正确答案：{q.answer}。{q.explanation}",
+                        error_type="no_answer",
+                        needs_review=False,
+                    )
+                )
+                continue
+
+            if q.type == "fill_blank":
+                # Fill-in-the-blank: case-insensitive, strip whitespace
+                is_correct = (
+                    user_answer.strip().lower() == str(q.answer).strip().lower()
+                )
+            else:
+                # single_choice / true_false: exact match
+                is_correct = user_answer.strip() == str(q.answer).strip()
+
+            results.append(
+                AnswerResult(
+                    question_id=q.id,
+                    user_answer=user_answer,
+                    is_correct=is_correct,
+                    score=1.0 if is_correct else 0.0,
+                    feedback=(
+                        q.explanation
+                        if is_correct
+                        else f"回答错误。正确答案：{q.answer}。{q.explanation}"
+                    ),
+                    error_type="none" if is_correct else "concept_confusion",
+                    needs_review=False,
+                )
+            )
+
+        return results