Add admin account with user management endpoints

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

backend/app/schemas/user.py

@@ -37,3 +37,25 @@ class Token(BaseModel):
 class LoginRequest(BaseModel):
     email: EmailStr
     password: str
+
+
+class AdminUserCreate(BaseModel):
+    email: EmailStr
+    password: str
+    display_name: Optional[str] = None
+
+
+class AdminPasswordReset(BaseModel):
+    new_password: str
+
+
+class AdminUserResponse(BaseModel):
+    id: int
+    email: str
+    display_name: Optional[str]
+    timezone: str
+    is_admin: bool
+    is_disabled: bool
+    created_at: datetime
+
+    model_config = {"from_attributes": True}