- Added related_documents ManyToMany field to Document model
- Created DocumentComment model with threading support (parent/replies)
- Created DocumentCommentViewSet with CRUD and permission checks
- Added endpoints for related documents:
* GET /documents/{id}/related/ - list related documents
* POST /documents/{id}/add_related/ - add related document
* POST /documents/{id}/remove_related/ - remove related document
- DocumentComment features:
* Threading support via parent field
* Edit tracking (is_edited flag)
* Author-only deletion (or staff)
* Depth calculation for nested comments
- Created migration 0010 for new fields and model
- Registered DocumentCommentViewSet in router
All medium-priority features complete!
igor_nadein
58e341e295