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/skills.py

@@ -0,0 +1,70 @@
+import uuid
+from typing import Annotated
+
+from fastapi import APIRouter, Depends, Query, status
+from sqlalchemy.ext.asyncio import AsyncSession
+
+from app.api.deps import get_current_user
+from app.database import get_db
+from app.models.user import User
+from app.schemas.skill import (
+    CreateSkillRequest,
+    SkillListResponse,
+    SkillResponse,
+    UpdateSkillRequest,
+)
+from app.services import skill_service
+
+router = APIRouter(prefix="/skills", tags=["skills"])
+
+
+@router.get("/", response_model=SkillListResponse)
+async def list_skills(
+    user: Annotated[User, Depends(get_current_user)],
+    db: Annotated[AsyncSession, Depends(get_db)],
+    include_general: bool = Query(default=True),
+):
+    skills = await skill_service.get_accessible_skills(db, user.id, include_general)
+    return SkillListResponse(skills=[SkillResponse.model_validate(s) for s in skills])
+
+
+@router.post("/", response_model=SkillResponse, status_code=status.HTTP_201_CREATED)
+async def create_skill(
+    data: CreateSkillRequest,
+    user: Annotated[User, Depends(get_current_user)],
+    db: Annotated[AsyncSession, Depends(get_db)],
+):
+    skill = await skill_service.create_personal_skill(db, user.id, **data.model_dump())
+    return SkillResponse.model_validate(skill)
+
+
+@router.get("/{skill_id}", response_model=SkillResponse)
+async def get_skill(
+    skill_id: uuid.UUID,
+    user: Annotated[User, Depends(get_current_user)],
+    db: Annotated[AsyncSession, Depends(get_db)],
+):
+    skill = await skill_service.get_skill(db, skill_id, user.id)
+    return SkillResponse.model_validate(skill)
+
+
+@router.patch("/{skill_id}", response_model=SkillResponse)
+async def update_skill(
+    skill_id: uuid.UUID,
+    data: UpdateSkillRequest,
+    user: Annotated[User, Depends(get_current_user)],
+    db: Annotated[AsyncSession, Depends(get_db)],
+):
+    skill = await skill_service.update_personal_skill(
+        db, skill_id, user.id, **data.model_dump(exclude_unset=True)
+    )
+    return SkillResponse.model_validate(skill)
+
+
+@router.delete("/{skill_id}", status_code=status.HTTP_204_NO_CONTENT)
+async def delete_skill(
+    skill_id: uuid.UUID,
+    user: Annotated[User, Depends(get_current_user)],
+    db: Annotated[AsyncSession, Depends(get_db)],
+):
+    await skill_service.delete_personal_skill(db, skill_id, user.id)