Phase 0.2: migrate UI component SVGs to lucide-react

- Button.tsx: Loader2 spinner
- EmptyState.tsx: FolderOpen default icon
- Modal.tsx: X close icon
- Pagination.tsx: ChevronLeft/ChevronRight
- Table.tsx: Loader2 loading spinner
- Toast.tsx: Check/X/AlertTriangle/Info + X close
- lucide-react v1.25.0 installed
- All 85 UI tests pass
- 2 pre-existing TSC errors in Dms.tsx (unrelated)

frontend/package.json

@@ -29,6 +29,7 @@
     "clsx": "^2.1.1",
     "i18next": "^23.14.0",
     "i18next-browser-languagedetector": "^8.0.0",
+    "lucide-react": "^1.25.0",
     "react": "^18.3.1",
     "react-dom": "^18.3.1",
     "react-hook-form": "^7.53.0",