- **refactor(main):** migrate static HTML to React components

- **feat(ui):** implement `AcknowledgeButton` component for acknowledging images
- **feat(stats):** add dashboard stats for total images, pending updates, and acknowledged status
- **chore(deps):** introduce `bun` dependency management and add required libraries
- **style(ui):** enhance UI with Tailwind-based components and modularity improvements
- **chore:** add drag-and-drop tag assignment using `@dnd-kit/core`

frontend/src/lib/time.ts

@@ -0,0 +1,17 @@
+export function timeAgo(iso: string): string {
+  const now = Date.now()
+  const then = new Date(iso).getTime()
+  const diff = Math.floor((now - then) / 1000)
+
+  if (diff < 60) return 'just now'
+  if (diff < 3600) {
+    const m = Math.floor(diff / 60)
+    return `${m} minute${m !== 1 ? 's' : ''} ago`
+  }
+  if (diff < 86400) {
+    const h = Math.floor(diff / 3600)
+    return `${h} hour${h !== 1 ? 's' : ''} ago`
+  }
+  const d = Math.floor(diff / 86400)
+  return `${d} day${d !== 1 ? 's' : ''} ago`
+}