feat: support Rolldown

[eltigerchino]

Testing integration with https://github.com/vitejs/rolldown-vite

TODOS

• set preserveEntrySignatures when it's implemented [Feature Request]: Support preserveEntrySignatures option / preserveSignatures in emitFile rolldown/rolldown#3500
• fix the rollupOptions.onwarn setting not silencing the non-existent hook import messages
• figure out how to get experimental.enableNativePlugins working https://vite.dev/guide/rolldown#enabling-native-plugins currently it causes styles to not be applied
• wait for build.watch to be implemented in vite rolldown
• replace esbuildOptions and transformWithEsbuild and other esbuild stuff in vite-plugin-svelte with the oxc/rolldown equivalent

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[benmccann]

removing this seems like it'd break when using esbuild. perhaps we should remove it only when using rolldown