refactor(B1): migrate to domain-driven project structure

Move all models/schemas/services/routers into app/domains/.
Keep backward-compat shims in old locations for imports.
Preserves domains/rendering/tasks.py from Phase A.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

backend/app/schemas/user.py

@@ -1,39 +1,3 @@
-import uuid
-from datetime import datetime
-from pydantic import BaseModel, EmailStr
-from app.models.user import UserRole
-
-
-class UserCreate(BaseModel):
-    email: EmailStr
-    password: str
-    full_name: str
-    role: UserRole = UserRole.client
-
-
-class UserUpdate(BaseModel):
-    full_name: str | None = None
-    is_active: bool | None = None
-    role: UserRole | None = None
-
-
-class UserOut(BaseModel):
-    id: uuid.UUID
-    email: str
-    full_name: str
-    role: UserRole
-    is_active: bool
-    created_at: datetime
-
-    model_config = {"from_attributes": True}
-
-
-class TokenResponse(BaseModel):
-    access_token: str
-    token_type: str = "bearer"
-    user: UserOut
-
-
-class LoginRequest(BaseModel):
-    email: EmailStr
-    password: str
+# Compat shim — use app.domains.auth.schemas instead
+from app.domains.auth.schemas import UserCreate, UserUpdate, UserOut, TokenResponse, LoginRequest
+__all__ = ["UserCreate", "UserUpdate", "UserOut", "TokenResponse", "LoginRequest"]