MVP-0: First Field Upload — UI with Dataset Explorer, Artifact Viewer, Mission Upload

- Dataset Explorer: list missions with processing status
- Artifact Viewer: mission details, metadata, processing status
- Mission Upload: simple video upload form
- React + Vite + React Router
- Proxy to API at localhost:3000

MVP-0 Acceptance Criteria:
✅ Upload video
✅ Create mission
✅ View mission in Dataset Explorer
✅ View artifact details
✅ See processing status

No AI. Just file transfer, storage, metadata, registry.

Next: Pilot 001 — First real field upload

packages/ui/src/App.tsx

@@ -0,0 +1,26 @@
+import { Routes, Route, Link } from 'react-router-dom';
+import DatasetExplorer from './pages/DatasetExplorer';
+import ArtifactViewer from './pages/ArtifactViewer';
+import MissionUpload from './pages/MissionUpload';
+
+function App() {
+  return (
+    <div style={{ fontFamily: 'system-ui, sans-serif', maxWidth: 1200, margin: '0 auto', padding: 20 }}>
+      <header style={{ borderBottom: '2px solid #333', paddingBottom: 20, marginBottom: 20 }}>
+        <h1>LandveX Intelligence Lab</h1>
+        <nav style={{ display: 'flex', gap: 20, marginTop: 10 }}>
+          <Link to="/">Dataset Explorer</Link>
+          <Link to="/upload">Mission Upload</Link>
+        </nav>
+      </header>
+
+      <Routes>
+        <Route path="/" element={<DatasetExplorer />} />
+        <Route path="/upload" element={<MissionUpload />} />
+        <Route path="/artifact/:id" element={<ArtifactViewer />} />
+      </Routes>
+    </div>
+  );
+}
+
+export default App;