Move manifest.json to the Output Directory's Parent in Vite 5

When using Vite 5 with a backend framework like Flask, you may need the manifest.json file placed outside the build output directory to prevent it from being URL-accessible. Vite (via Rollup) does not support relative paths in the manifest config option. Two workarounds are presented: the simple approach of appending a shell `mv` command to the build script in package.json, and a more robust approach of writing a custom Vite plugin that uses the `writeBundle` hook to rename/move the manifest file after the build completes. The plugin approach is more maintainable when output directory or manifest filenames change.