Add Typefully thread + video queueing

## Summary
Implement a Typefully integration that queues patch notes as threaded posts with optional video uploads.

## Acceptance Criteria
1. Supabase migration creates `typefully_configs` and `typefully_jobs` tables.
2. Integration UI lets users store credentials and view the Typefully card alongside existing integrations.
3. Server-side helpers manage authentication, thread creation, and video upload to Typefully.
4. API route renders video via Remotion, queues Typefully thread, and records job metadata.
5. Patch note detail page exposes "Queue Twitter thread" action with state feedback.
6. Documentation covers new environment variables, rendering requirements, and references API limitations.
7. Playwright E2E coverage exercises queueing a thread (with mock video upload) and must pass in CI before closing the issue.

## Notes
- Mirror patterns from the Resend integration for UI/UX consistency.
- Reference the Typefully API documentation when building the integration: https://support.typefully.com/en/articles/8718287-typefully-api

Start by examining the existing Resend integration for UI and server-side patterns, then review the Supabase migration, Remotion rendering flow, patch note detail page, and API route entry points. Implement the listed Typefully configuration, queueing, documentation, and Playwright E2E requirements; done means the mocked upload flow passes in CI and all acceptance criteria are covered.

Written by the indexing model from the issue text.