docs: add note to set CLOUDFLARE_ENV for wrangler to load correct env vars

Author: lotap

docs/start/framework/react/guide/environment-variables.md

@@ -98,6 +98,16 @@ TanStack Start automatically loads environment files in this order:
 .env                # Default variables (commit to git)
 ```
 
+> [!TIP]
+> When using the Cloudflare Vite plugin, set `CLOUDFLARE_ENV` to ensure Wrangler loads the correct environment
+>
+> ```bash
+>  # .env.development
+>  CLOUDFLARE_ENV=development
+> ```
+>
+> Otherwise, the variables defined in your `.env.<environment>` files may not be read or injected into `process.env`
+
 ### Example Setup
 
 **.env** (committed to repository):

docs/start/framework/solid/guide/environment-variables.md

@@ -98,6 +98,16 @@ TanStack Start automatically loads environment files in this order:
 .env                # Default variables (commit to git)
 ```
 
+> [!TIP]
+> When using the Cloudflare Vite plugin, set `CLOUDFLARE_ENV` to ensure Wrangler loads the correct environment
+>
+> ```bash
+>  # .env.development
+>  CLOUDFLARE_ENV=development
+> ```
+>
+> Otherwise, the variables defined in your `.env.<environment>` files may not be read or injected into `process.env`
+
 ### Example Setup
 
 **.env** (committed to repository):