build: include render artifacts in the default production build

[ubugeeei]

Finding

npm run build creates the Studio app and Electron main output, but does not create dist-render. In packaged/bin mode, Electron resolves the render page from dist-render/render.html.

Evidence

• package.json build runs build:vite and build:electron only.
• package.json build:all adds build:render separately.
• electron/main.ts getRenderPageUrl points to dist-render/render.html when not using the dev server.

Acceptance criteria

• Make the production build command produce all runtime artifacts, or rename scripts so partial/full builds are unambiguous.
• Update README/docs accordingly.
• Verify the chosen command from a clean checkout.

[ubugeeei]

対応済みです。修正は PR #1 / commit 9cf4498 に反映済みです。