fix: set useDefineForClassFields to false in tsup swc config

[isatiso]

Problem

tsup's swcPlugin (activated by emitDecoratorMetadata: true) intercepts all .ts files via an esbuild onLoad hook and transforms them with SWC instead of esbuild. The plugin hardcodes jsc.target: "es2022" and does not pass useDefineForClassFields: false, so SWC preserves native ES class field syntax.

This causes class field initializers to execute before constructor parameter assignments at runtime:

var HttpServer = class {
  config_data;                                          // undefined
  port = this.config_data.get('http.port');              // TypeError!
  constructor(injector, config_data) {
    this.config_data = config_data;                     // too late
  }
}

Fix

Add a root-level tsup.config.ts that sets swc.jsc.transform.useDefineForClassFields: false. tsup's config resolution (via joycon) walks up from each package directory, so all packages automatically pick up this config.

After the fix, the output correctly moves field initializers into the constructor body, after parameter assignments:

var HttpServer = class {
  constructor(injector, config_data) {
    this.injector = injector;
    this.config_data = config_data;
    this.sockets = new Set();
    this.port = this.config_data.get('http.port');       // works
    this.keepalive_timeout = this.config_data.get('http.server.keepalive_timeout');
    this.terminate_timeout = this.config_data.get('http.server.terminate_timeout') ?? 4000;
  }
}

Verification

• pnpm -r build passes, all packages use the root config
• pnpm -r test passes (1 pre-existing network-dependent failure in rabbitmq unrelated to this change)