feat(delivery): stream task updates with SSE

frontend/src/api/delivery.ts

@@ -72,6 +72,11 @@ export interface TaskEvent {
   created_at: string
 }
 
+export interface DeliveryTaskSnapshot {
+  task: DeliveryTask
+  events: TaskEvent[]
+}
+
 export const deliveryApi = {
   async listTargets(): Promise<DeliveryTarget[]> {
     const data = await authRequest('/auth/api/v1/delivery/targets?component=mysql')
@@ -112,6 +117,14 @@ export const deliveryApi = {
       method: 'POST',
     })
   },
+
+  streamTask(taskId: string): EventSource {
+    const token = getToken()
+    const search = new URLSearchParams()
+    if (token) search.set('access_token', token)
+    const query = search.toString()
+    return new EventSource(`/auth/api/v1/delivery/tasks/${encodeURIComponent(taskId)}/stream${query ? `?${query}` : ''}`)
+  },
 }
 
 function createIdempotencyKey(payload: CreateMySQLDeliveryPayload) {