docs: add routing page (#9550)

- Add a new homepage to `book` project for the routing page
- Move all main doc pages to be under `/v2/learn` (and added redirects + fixed links across docs)
- Other: add admin components to resources dropdown + fixes to search on mobile.

Closes DX-955

Preview: https://docs-v2-git-docs-router-page-medusajs.vercel.app/v2

www/apps/book/app/learn/advanced-development/custom-cli-scripts/page.mdx

@@ -0,0 +1,72 @@
+export const metadata = {
+  title: `${pageNumber} Custom CLI Scripts`,
+}
+
+# {metadata.title}
+
+In this chapter, you'll learn how create and execute custom scripts from Medusa's CLI tool.
+
+## What is a Custom CLI Script?
+
+A custom CLI script is a function to execute through Medusa's CLI tool. This is useful when creating custom Medusa tooling to run through the CLI.
+
+---
+
+## How to Create a Custom CLI Script?
+
+To create a custom CLI script, create a TypeScript or JavaScript file under the `src/scripts` directory. The file must default export a function.
+
+For example, create the file `src/scripts/my-script.ts` with the following content:
+
+```ts title="src/scripts/my-script.ts"
+import { 
+  ExecArgs,
+  IProductModuleService,
+} from "@medusajs/framework/types"
+import { Modules } from "@medusajs/framework/utils"
+
+export default async function myScript({ container }: ExecArgs) {
+  const productModuleService: IProductModuleService = container.resolve(
+    Modules.PRODUCT
+  )
+
+  const [, count] = await productModuleService
+    .listAndCountProducts()
+
+  console.log(`You have ${count} product(s)`)
+}
+```
+
+The function receives as a parameter an object having a `container` property, which is an instance of the Medusa Container. Use it to resolve resources in your Medusa application.
+
+---
+
+## How to Run Custom CLI Script?
+
+To run the custom CLI script, run the Medusa CLI's `exec` command:
+
+```bash
+npx medusa exec ./src/scripts/my-script.ts
+```
+
+---
+
+## Custom CLI Script Arguments
+
+Your script can accept arguments from the command line. Arguments are passed to the function's object parameter in the `args` property.
+
+For example:
+
+```ts
+import { ExecArgs } from "@medusajs/framework/types"
+
+export default async function myScript({ args }: ExecArgs) {
+  console.log(`The arguments you passed: ${args}`)
+}
+```
+
+Then, pass the arguments in the `exec` command after the file path:
+
+```bash
+npx medusa exec ./src/scripts/my-script.ts arg1 arg2
+```