Phase 3: Skills & Context — skill system, personal context, context layering

Backend:
- Skill model + migration (with FK on chats.skill_id)
- Personal + general skill CRUD services with access isolation
- Admin skill CRUD endpoints (POST/GET/PATCH/DELETE /admin/skills)
- User skill CRUD endpoints (POST/GET/PATCH/DELETE /skills/)
- Personal context GET/PUT at /users/me/context
- Extended context assembly: primary + personal context + skill prompt
- Chat creation/update now accepts skill_id with validation

Frontend:
- Skill selector dropdown in chat header (grouped: general + personal)
- Reusable skill editor form component
- Admin skills management page (/admin/skills)
- Personal skills page (/skills)
- Personal context editor page (/profile/context)
- Updated sidebar: Skills, My Context nav items + admin skills link
- English + Russian translations for all skill/context UI

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

backend/app/api/v1/router.py

@@ -3,12 +3,16 @@ from fastapi import APIRouter
 from app.api.v1.auth import router as auth_router
 from app.api.v1.chats import router as chats_router
 from app.api.v1.admin import router as admin_router
+from app.api.v1.skills import router as skills_router
+from app.api.v1.users import router as users_router
 
 api_v1_router = APIRouter(prefix="/api/v1")
 
 api_v1_router.include_router(auth_router)
 api_v1_router.include_router(chats_router)
 api_v1_router.include_router(admin_router)
+api_v1_router.include_router(skills_router)
+api_v1_router.include_router(users_router)
 
 
 @api_v1_router.get("/health")