#38957 chore: migrate rooms.leave endpoint to new OpenAPI pattern with AJV validation

Proposed changes (including videos or screenshots)

Migrates the rooms.leave endpoint from the legacy API.v1.addRoute
pattern to the new OpenAPI-compliant format using AJV schema validation,
continuing the REST API migration effort.

Tracked in: RocketChat/Rocket.Chat-Open-API#150

Key changes:

• Replaced API.v1.addRoute with chained .post() for rooms.leave
• Added declarative AJV body schema with anyOf constraint supporting
  either roomId or roomName
• Added explicit response schemas for 200, 400, and 401 status codes
• Removed manually written type from packages/rest-typings/src/v1/rooms.ts
  since it is now auto-generated via ExtractRoutesFromAPI
• Added changeset file
• Business logic unchanged

Swagger UI — endpoint documented at /api-docs/:

400 response — validation and business logic working correctly:

Steps to test or reproduce

1. Run the server locally with yarn dev
2. Navigate to http://localhost:3000/api-docs/
3. Authorize with X-Auth-Token and X-User-Id
4. Find POST /api/v1/rooms.leave
5. Execute with valid body: { "roomName": "general" }
6. Execute with empty body {} to confirm 400 validation error

Further comments

Follows the same migration pattern established in #35995 (rooms.favorite).

Summary by CodeRabbit

• Chores
  • Migrated the rooms.leave API to a new validated endpoint for more robust request handling and clearer error responses.
• Documentation
  • Added a release changeset noting the patch bump and the endpoint migration.

COMM-144
Task: ARCH-1987