feat(downloads): front-and-center "active now" panel with live elapsed timers

New ActiveDownloadsPanel pinned at the top of the Downloads tab shows what's
running (pulsing dot + live mm:ss timer counting from started_at) and what's
queued, so the operator can see activity at a glance without the running
filter. Backed by store.loadActive() which fetches running + pending
independent of the feed filter; refreshed every 4s by the existing live poll.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

frontend/src/stores/downloads.js

@@ -18,6 +18,10 @@ export const useDownloadsStore = defineStore('downloads', () => {
   const stats = ref({ pending: 0, running: 0, ok: 0, error: 0, skipped: 0 })
   const activity = ref({ hours: 24, buckets: [] })
   const failing = ref([])
+  // Running + queued events, fetched independent of the feed's filter so
+  // the "active now" panel always reflects what's happening regardless of
+  // how the operator has filtered the historical list below.
+  const activeEvents = ref([])
 
   function _params(extra = {}) {
     const out = { limit: 50, ...extra }
@@ -75,10 +79,19 @@ export const useDownloadsStore = defineStore('downloads', () => {
     return failing.value
   }
 
+  async function loadActive() {
+    const [running, pending] = await Promise.all([
+      api.get('/api/downloads', { params: { status: 'running', limit: 50 } }),
+      api.get('/api/downloads', { params: { status: 'pending', limit: 50 } }),
+    ])
+    activeEvents.value = [...running, ...pending]
+    return activeEvents.value
+  }
+
   return {
     events, cursor, hasMore, filter, selected, loading, error, stats,
-    activity, failing,
+    activity, failing, activeEvents,
     loadFirst, loadMore, loadOne, applyFilter, closeDetail, loadStats,
-    loadActivity, loadFailing,
+    loadActivity, loadFailing, loadActive,
   }
 })