docs: update all SRS documents to reflect implemented state

- ENCOACH_UNIFIED_SRS.md v2.0: updated header, added 8 new Part VIII-B
  sections (student leave, fees, lessons, gradebook, student progress,
  library, activities, facilities), extended permissions with roles CRUD
  and authority matrix, updated tech specs (93 pages, ~377 API routes,
  41 modules), added implementation traceability to all sections
- ENCOACH_ODOO19_BACKEND_SRS.md v3.0: updated status to implemented,
  added beyond-SRS features section, updated module count to 41,
  endpoint count to ~377
- ODOO_DEVELOPER_HANDOFF.md: rewritten with current repo references
  and implementation status
- ENCOACH_SYSTEM_FEATURES_GUIDE.md: added system features guide
- Superseded notices added to ODOO_BACKEND_SRS_v3.md,
  ODOO_MIGRATION_SRS_v2.md, ODOO_MIGRATION_SRS.md,
  ODOO_MIGRATION_FRONTEND_SRS.md, MATH_IT_ADAPTIVE_LEARNING_SRS.md

Made-with: Cursor

docs/ODOO_BACKEND_SRS_v3.md

@@ -1,8 +1,10 @@
 # EnCoach Odoo 19 Backend -- Developer SRS v3
 
+> **SUPERSEDED** -- This document has been replaced by `ENCOACH_ODOO19_BACKEND_SRS.md` (v3.0) and `ENCOACH_UNIFIED_SRS.md` (v2.0). All content below is historical. The developer has implemented everything and the system is deployed at `http://5.189.151.117:8069`.
+
 **Document Version:** 3.0
 **Date:** March 11, 2026
-**Status:** Active -- Ready for Development
+**Status:** ~~Active -- Ready for Development~~ **SUPERSEDED**
 **Supersedes:** `ODOO_MIGRATION_SRS_v2.md` (v2.0)
 **Master Reference:** `ENCOACH_UNIFIED_SRS.md` (v1.0)
 **Author:** EnCoach Architecture Team