docs: add .env symlink setup instructions for apps/web (#287)

Co-authored-by: Claude <[email protected]>

apps/docs/get-started/local.mdx

@@ -98,6 +98,14 @@ pnpm install
 
 ```bash
 openssl rand -base64 32
+```
+
+  </Step>
+  <Step title="Create symlink for Next.js">
+  Create a symlink so that Next.js can access the root `.env` file:
+
+```bash
+ln -s ../../.env apps/web/.env
 ```
 
   </Step>