dotnet pack embeds dev-mode frontend bundles — sm pack must force a production Vite build

[antosubash]

Found during module-packaging Session 1 checkpoint.

Packing SimpleModule.FeatureFlags after a dev workspace build put a ~1.3 MB unminified Manage-*.mjs chunk (plus 2.8 MB source map) into the nupkg's staticwebassets. The JsBuild target reuses whatever the last Vite build produced.

sm pack (Session 2) should force a production build (minified, no source maps — or maps stripped from the package) and fail closed if the bundle does not externalize react / react-dom / @inertiajs/react / SimpleModule.UI.

[webbrain-one]

Thanks for catching this! I've opened a PR to address it: #291

This update modifies sm pack to explicitly trigger a production Vite build before packaging. It ensures the bundled assets are minified, strips source maps from the final nupkg, and adds a build-time validation that fails if required dependencies (react, react-dom, @inertiajs/react, and SimpleModule.UI) aren't properly externalized.

Let me know if you have any questions or feedback during review!