feat: Implement admin user management endpoints and user update schema

app/schemas/user.py

@@ -0,0 +1,14 @@
+"""User schemas."""
+
+from pydantic import BaseModel, Field
+
+
+class UserUpdate(BaseModel):
+    """Schema for updating a user."""
+
+    name: str | None = Field(
+        None, min_length=1, max_length=100, description="User full name",
+    )
+    plan_id: int | None = Field(None, description="User plan ID")
+    credits: int | None = Field(None, ge=0, description="User credits")
+    is_active: bool | None = Field(None, description="Whether user is active")