Implements IMessageConnector (auth_type='local') that opens ~/Library/Messages/chat.db
read-only, converts Apple nanosecond timestamps to UTC datetimes, and yields one
Document per message with handle-based author resolution and chat display names.
Includes 8 tests using a temporary SQLite DB and 2 MCP tools (search + get conversation).
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
