Replace `as any` cast with `as unknown as ReturnType<typeof createMeiliClient>`
in the mock client factory. This preserves type safety without requiring the mock
to implement the full SDK interface.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Implements Task 2 of Plan 4 (Archive & Search): provides createMeiliClient,
configureIndex, indexMessage, and deleteMessage for use by the worker and API.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>