improve: vite-plugin-react-scan readme and error message

Author: pivanov

packages/vite-plugin-react-scan/README.md

@@ -15,6 +15,8 @@ pnpm add -D @react-scan/vite-plugin-react-scan react-scan
 yarn add -D @react-scan/vite-plugin-react-scan react-scan
 ```
 
+> **Note:** Make sure `react-scan` is installed as a peer dependency. The plugin will automatically locate it in your project's dependency tree.
+
 ## Usage
 
 Add the plugin to your `vite.config.ts`:

packages/vite-plugin-react-scan/src/index.ts

@@ -293,6 +293,9 @@ const reactScanPlugin = (options: ReactScanPluginOptions = {}): Plugin => {
           log.debug('Emitted react-scan as asset:', assetFileName);
         } catch (error) {
           log.error('Failed to process react-scan:', error);
+          throw new Error(
+            `Module ${REACT_SCAN_IDENTIFIER} not found. Please ensure react-scan is installed as a peer dependency.`
+          );
         }
       }
     },