feat(01-02): implement IMAP connection service with authentication and folder listing

- Created IMAPService class with async connect/list_folders/close methods
- Uses aioimaplib for async IMAP4_SSL operations
- Implements proper connection cleanup with logout() not close()
- Added aioimaplib and html2text dependencies to pyproject.toml
- Follows async patterns from existing service classes (ynab_service.py, mealie_service.py)
- Includes comprehensive logging with [IMAP] and [IMAP ERROR] prefixes

pyproject.toml

@@ -35,6 +35,8 @@ dependencies = [
     "jq>=1.10.0",
     "tavily-python>=0.7.17",
     "ynab>=1.3.0",
+    "aioimaplib>=2.0.1",
+    "html2text>=2025.4.15",
 ]
 
 [tool.aerich]