﻿Write a SpacetimeDB backend module in Rust that defines one table and two reducers for client lifecycle events.

TABLE
- event
  - Struct: Event
  - Fields:
    - id: i32 (primary key, auto-increment)
    - kind: String

REDUCERS
- client_connected: when a client connects, insert exactly one row into event with kind="connected"
- client_disconnected: when a client disconnects, insert exactly one row into event with kind="disconnected"
