chore: import upstream snapshot with attribution

apps/sim/lib/core/utils/browser-polyfills.ts

@@ -0,0 +1,47 @@
+/**
+ * Polyfills for `Promise.withResolvers` (Safari < 17.4, Chrome < 119) and
+ * `URL.parse` (Safari < 18, Chrome < 126), which pdf.js 5.x calls at
+ * module-evaluation time. Without them, importing `react-pdf`/`pdfjs-dist`
+ * throws before anything renders, so this module must be imported for its
+ * side effects BEFORE those imports. The pdf.js worker runs in a separate
+ * context these polyfills cannot reach; it is covered by serving pdf.js's
+ * self-polyfilling legacy worker build (see pdf-viewer.tsx).
+ *
+ * Typed locally because the repo TS lib is ES2022, which predates both APIs.
+ */
+
+interface PromiseWithResolversResult<T> {
+  promise: Promise<T>
+  resolve: (value: T | PromiseLike<T>) => void
+  reject: (reason?: unknown) => void
+}
+
+const promiseCtor = Promise as typeof Promise & {
+  withResolvers?: <T>() => PromiseWithResolversResult<T>
+}
+
+if (typeof promiseCtor.withResolvers !== 'function') {
+  promiseCtor.withResolvers = <T>(): PromiseWithResolversResult<T> => {
+    let resolve!: (value: T | PromiseLike<T>) => void
+    let reject!: (reason?: unknown) => void
+    const promise = new Promise<T>((res, rej) => {
+      resolve = res
+      reject = rej
+    })
+    return { promise, resolve, reject }
+  }
+}
+
+const urlCtor = URL as typeof URL & {
+  parse?: (url: string | URL, base?: string | URL) => URL | null
+}
+
+if (typeof urlCtor.parse !== 'function') {
+  urlCtor.parse = (url: string | URL, base?: string | URL): URL | null => {
+    try {
+      return new URL(url, base)
+    } catch {
+      return null
+    }
+  }
+}