build(site): [SITE-07] reproduce and validate Monaco language modes

scripts/site-vendor/monaco/compiler.ts

@@ -0,0 +1,34 @@
+import assert from 'node:assert/strict'
+
+export interface CompilerModule { name: string, source: string }
+
+// Reproduce emission with pinned standard libraries and optional verified module
+// declarations. This is intentionally not a full upstream semantic typecheck.
+export function emitAmd(ts: typeof import('typescript'), source: string, libraries: string[], strict = false, modules: CompilerModule[] = []): string {
+  const options: import('typescript').CompilerOptions = {
+    target: ts.ScriptTarget.ES5,
+    module: ts.ModuleKind.AMD,
+    newLine: ts.NewLineKind.LineFeed,
+    noResolve: modules.length === 0,
+    lib: libraries.map(library => `lib.${library}.d.ts`),
+    strict,
+  }
+  const host = ts.createCompilerHost(options)
+  const getSourceFile = host.getSourceFile.bind(host)
+  const inputs = new Map([['worker.ts', source], ...modules.map((module, index): [string, string] => [`pinned-${index}.d.ts`, module.source])])
+  host.getSourceFile = (file, languageVersion, onError, createNew) => inputs.has(file)
+    ? ts.createSourceFile(file, inputs.get(file)!, languageVersion, true)
+    : getSourceFile(file, languageVersion, onError, createNew)
+  host.resolveModuleNames = names => names.map((name) => {
+    const index = modules.findIndex(module => module.name === name)
+    return index < 0 ? undefined : { resolvedFileName: `pinned-${index}.d.ts`, extension: ts.Extension.Dts }
+  })
+  let output = ''
+  host.writeFile = (file, text) => {
+    assert(file.endsWith('.js') && !output, 'Unexpected compiler output')
+    output = text
+  }
+  const result = ts.createProgram(['worker.ts'], options, host).emit()
+  assert(!result.emitSkipped && output, 'Missing source emission')
+  return output
+}