feat(ui): rewrite frontend in React with Vite

- Scaffold Vite+React project in frontend/ (bun, react 18, @vitejs/plugin-react)
- vite.config.js outputs to crates/archivr-server/static/ directly
- src/utils.js: formatBytes, valueText, formatTimestamp, SOURCE_ICONS, sourceIconSvg
- src/api.js: typed fetch wrappers for all API endpoints
- App.jsx: full state management, archive switching, debounced search,
  tag filter, view routing, capture dialog orchestration
- components/Topbar.jsx: archive switcher, nav, capture button
- components/CaptureDialog.jsx: native <dialog> ref with showModal/close,
  Escape key support, locator validation
- components/EntriesView.jsx + EntryRow.jsx: flex table with source icons,
  type pills, keyboard selection
- components/ContextRail.jsx: parallel detail+tags fetch, stale-race guard
  via selectSeqRef, inline tag assign/remove
- components/RunsView.jsx: runs kept as <table> (matches original)
- components/AdminView.jsx: mounted archives list
- components/TagsView.jsx: recursive tag tree with active state
- Remove old app.js; styles.css moved to frontend/src/ (Vite bundles it)

frontend/src/components/RunsView.jsx

@@ -0,0 +1,24 @@
+export default function RunsView({ runs }) {
+  return (
+    <section id="runs-view" className="view is-active">
+      <table className="entry-table">
+        <thead>
+          <tr>
+            <th>Started</th><th>Status</th><th>Requested</th><th>Completed</th><th>Failed</th>
+          </tr>
+        </thead>
+        <tbody>
+          {runs.map((run, i) => (
+            <tr key={i}>
+              <td>{run.started_at ?? ''}</td>
+              <td>{run.status ?? ''}</td>
+              <td>{run.requested_count ?? ''}</td>
+              <td>{run.completed_count ?? ''}</td>
+              <td>{run.failed_count ?? ''}</td>
+            </tr>
+          ))}
+        </tbody>
+      </table>
+    </section>
+  )
+}