Why doesn't the flag --env.NODE_ENV and the option --onSuccess take effect?

I would like the generated results to be automatically executed following the successful completion of the compilation process, and for that compilation to utilize the configuration corresponding to the specific environment.

```json
"scripts": {
"dev": "tsup --watch --env.NODE_ENV development --onSuccess 'node dist/app.js'"
}
```
```ts
// tsup.config.ts
import { defineConfig } from "tsup";

const isDev = process.env.NODE_ENV === "development";

console.log("isDev", process.env.NODE_ENV);

export default defineConfig({
target: "es2020",
entry: ["lib/app.ts"],
outDir: "dist",
format: ["cjs", "esm"],
dts: !isDev,
minify: !isDev,
clean: true,
sourcemap: isDev
});
```

result:


Why doesn't the flag `--env.NODE_ENV` and the option `--onSuccess` take effect?
What should I do?

Reproduce the package script using tsup.config.ts and the shown --watch, --env.NODE_ENV, and --onSuccess options. Start by tracing how the CLI loads tsup.config.ts and handles those options; done means the environment-specific settings are applied and node dist/app.js runs after a successful compilation.

Written by the indexing model from the issue text.