1.4.1: nested pages dirs, CommonJS require of react in client bundles

- Page URL paths are now relative to src/pages. The old greedy
  `.*/pages/` cut mapped src/pages/admin/pages/index.tsx to /index, so
  every page under a nested `pages` directory collided with the home page
  and was never bundled. SSR also tells API routes by URL path now.
- CommonJS `require("react…")` in client bundles (for example
  use-sync-external-store/shim, pulled in by MUI) threw "Dynamic require
  of "react" is not supported" in the browser. Those requires now go
  through a small bundled ESM module that imports the external.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

dist/utils/grab-all-pages.d.ts

@@ -5,4 +5,13 @@ type Params = {
     include_server?: boolean;
 };
 export default function grabAllPages(params?: Params): PageFiles[];
+/**
+ * The URL path is the file's path relative to the pages root, so a nested
+ * directory that happens to be called `pages` (e.g. `src/pages/admin/pages/
+ * index.tsx` -> `/admin/pages/index`) is kept, not treated as the root.
+ */
+export declare function grabPageFileObject({ file_path, pages_root, }: {
+    file_path: string;
+    pages_root: string;
+}): PageFiles | undefined;
 export {};