Documentation gaps: 4 undocumented API endpoints

[evan-zhang11]

Description

Several implemented API endpoints are missing from docs/dev/behaviors.md:

1. PATCH /api/files/:id/zoom — update minZoom/maxZoom for a file
2. GET /api/workspaces/archived — list archived workspaces
3. DELETE /api/fonts/:id — delete font (API-021 only covers publish/unpublish)
4. POST /api/workspaces/:id/leave — leave a workspace

Found during daily documentation review (2026-05-08).

Tasks

• Add behaviors.md entries for each endpoint
• Verify test coverage exists