docs: added troubleshooting for using pnpm (#8537)

www/apps/resources/app/troubleshooting/pnpm-errors/page.mdx

@@ -0,0 +1,11 @@
+export const metadata = {
+  title: `pnpm Errors`,
+}
+
+# {metadata.title}
+
+If you're using `pnpm` and you face errors in your Medusa application, such as `Failed with error The "path" argument must be of type string. Received undefined`, add the file `.npmrc` in the root of your Medusa project directory with the following content:
+
+```bash
+node-linker=hoisted
+```

www/apps/resources/sidebar.mjs

@@ -1739,6 +1739,10 @@ export const sidebar = sidebarAttachHrefCommonOptions([
                 path: "/troubleshooting/errors-installing-cli",
                 title: "Errors Installing CLI",
               },
+              {
+                path: "/troubleshooting/pnpm-errors",
+                title: "pnpm Errors",
+              },
               {
                 path: "/troubleshooting/general-errors",
                 title: "General Errors",