- Introduced WS_Message_V3 standardized Pydantic model and WS_Manager_V3.
- Implemented /v3/ws/ endpoint with granular Redis routing to solve "noisy neighbor" scaling issues.
- Added presence tracking using Redis Sets for group coordination.
- Comprehensive test suite added (unit and integration) covering models, manager, and routing logic.
- Documentation: Created V3 Frontend WebSocket Guide and Project design spec.
- Updated main Frontend API guide and tests README with new standards.
- Moved 29 unreferenced legacy router files to app/routers/archive/
- Restored and registered 'websockets' router in registry.py (exempted from deprecation)
- Cleaned up registry imports and verified application compilation.
- Added DeprecationParams dependency to log warnings when legacy routes are accessed.
- Updated setup_routers to apply deprecation warnings to non-V3 legacy endpoints.
- Exempted core infrastructure, special routers, and routers currently in use from deprecation warnings.
- Cleaned up 24 unused router imports from the registry.
