Added:

- Messenger, Mercure
- chapter download flow (lelscan only)

assets/controllers/mercure_controller.js

@@ -0,0 +1,33 @@
+import {Controller} from '@hotwired/stimulus';
+
+/*
+* The following line makes this controller "lazy": it won't be downloaded until needed
+* See https://github.com/symfony/stimulus-bridge#lazy-controllers
+*/
+/* stimulusFetch: 'lazy' */
+export default class extends Controller {
+  // ...
+  connect() {
+    const topic = this.data.get('topic');
+    const mercureHubUrl = 'https://localhost/.well-known/mercure';
+    const eventSource = new EventSource(`${mercureHubUrl}?topic=${topic}`);
+
+    eventSource.onmessage = (event) => {
+      const data = JSON.parse(event.data);
+      console.log('Received Mercure update:', data);
+
+      this.dispatchAlert(data.message, data.status);
+    };
+
+    eventSource.onerror = (event) => {
+      console.error('EventSource failed:', event);
+    };
+  }
+
+  dispatchAlert(message, level) {
+    const event = new CustomEvent('alert:show', {
+      detail: { message: message, level: level }
+    });
+    window.dispatchEvent(event);
+  }
+}