Paginate beta history and refresh pages from events

src/lib/ui/stores/pipeline.ts

@@ -26,6 +26,11 @@ function updateDeployment(id: string, mutate: (d: PipelineDeployment) => void):
 export function startPipelineStream(): (() => void) | undefined {
     if (!browser || source) return;
     source = new EventSource('/api/events/pipeline');
+    source.addEventListener('open', () => window.dispatchEvent(new Event('ec:pipeline-connected')));
+    source.addEventListener('beta-changed', event => {
+        try { window.dispatchEvent(new CustomEvent('ec:beta-changed', { detail: JSON.parse((event as MessageEvent).data) })); }
+        catch { /* Reconnect refreshes authoritative state if an event is malformed. */ }
+    });
     for (const event of ['server-changed', 'server-state', 'deployment-opened', 'fleet-invalidated']) {
         source.addEventListener(event, () => window.dispatchEvent(new Event('ec:fleet-changed')));
     }