Write a SpacetimeDB backend module in TypeScript that demonstrates looking up rows by primary key and writing projections.

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

- result
  - Fields:
    - id: number (i32, primary key)
    - name: string

REDUCERS
- lookupUserName: given id:number, find user by id, insert projection (id, name) into result table
