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/schemas/chat.py

@@ -6,11 +6,13 @@ from pydantic import BaseModel, Field
 
 class CreateChatRequest(BaseModel):
     title: str | None = None
+    skill_id: uuid.UUID | None = None
 
 
 class UpdateChatRequest(BaseModel):
     title: str | None = None
     is_archived: bool | None = None
+    skill_id: uuid.UUID | None = None
 
 
 class SendMessageRequest(BaseModel):

backend/app/schemas/skill.py

@@ -0,0 +1,40 @@
+import uuid
+from datetime import datetime
+
+from pydantic import BaseModel, Field
+
+
+class CreateSkillRequest(BaseModel):
+    name: str = Field(min_length=1, max_length=100)
+    description: str | None = None
+    system_prompt: str = Field(min_length=1)
+    icon: str | None = None
+    is_active: bool = True
+    sort_order: int = 0
+
+
+class UpdateSkillRequest(BaseModel):
+    name: str | None = Field(default=None, min_length=1, max_length=100)
+    description: str | None = None
+    system_prompt: str | None = Field(default=None, min_length=1)
+    icon: str | None = None
+    is_active: bool | None = None
+    sort_order: int | None = None
+
+
+class SkillResponse(BaseModel):
+    id: uuid.UUID
+    user_id: uuid.UUID | None
+    name: str
+    description: str | None
+    system_prompt: str
+    icon: str | None
+    is_active: bool
+    sort_order: int
+    created_at: datetime
+
+    model_config = {"from_attributes": True}
+
+
+class SkillListResponse(BaseModel):
+    skills: list[SkillResponse]