Write a SpacetimeDB backend module in TypeScript that defines one table and a reducer that updates a row.

TABLE
- user
  - Fields:
    - id: number (i32, primary key)
    - name: string
    - age: number (i32)
    - active: boolean

REDUCERS
- updateUser: given id:number, name:string, age:number, active:boolean, update the row with matching id
  - (id=id, name=name, age=age, active=active)
