build: migrate manualChunks to function form for Vite 8 / Rolldown

Vite 8 switches the bundler to Rolldown, which no longer accepts the
object form of rollupOptions.output.manualChunks — it must be a function.
Convert it (same ndk/vendor split intent) and give tsconfig.node.json a
modern target/lib so vite.config.ts type-checks against String.includes.

tsconfig.node.json

@@ -2,6 +2,8 @@
   "compilerOptions": {
     "composite": true,
     "skipLibCheck": true,
+    "target": "ES2022",
+    "lib": ["ES2023"],
     "module": "ESNext",
     "moduleResolution": "bundler",
     "allowSyntheticDefaultImports": true