Exclude the 'backend' folder from the Vite watcher.

This avoids unnecessary reloads when working on the backend.

vite.config.ts

@@ -35,7 +35,10 @@ export default defineConfig({
 		APP_BUILD_HASH: JSON.stringify(process.env.APP_BUILD_HASH || 'dev-build')
 	},
 	build: {
-		sourcemap: true
+		sourcemap: true,
+		watch: {
+			exclude: ['backend']
+		}
 	},
 	worker: {
 		format: 'es'