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/pptx/ooxml/scripts/validation/__init__.py

@@ -0,0 +1,15 @@
+"""
+Validation modules for Word document processing.
+"""
+
+from .base import BaseSchemaValidator
+from .docx import DOCXSchemaValidator
+from .pptx import PPTXSchemaValidator
+from .redlining import RedliningValidator
+
+__all__ = [
+    "BaseSchemaValidator",
+    "DOCXSchemaValidator",
+    "PPTXSchemaValidator",
+    "RedliningValidator",
+]