feat: implement code modernization and testing infrastructure

- TypeScript: Enable checkJs with type declarations for Cesium/satellite.js/hls.js
- Code Decomposition: Extract utilities from monolithic components
  - src/constants/cities.js: 140+ cities organized by strategic tiers
  - src/constants/globe.js: Globe constants, track views, layer budgets
  - src/utils/geo.js: Geographic math helpers
  - src/utils/entityMap.js: Entity ID to layer mapping
  - src/utils/adsbParser.js: ADS-B payload parsing
  - src/utils/aircraftClassification.js: Flight classification
  - src/utils/cache.js: IndexedDB browser cache
  - src/utils/entityCulling.js: Viewport culling & pagination
- Testing: Add 127 unit tests covering utilities and integration
  - Tests for geo, layerHealth, cities, entityMap, globe, cache
  - Tests for adsbParser, aircraftClassification, entityCulling
  - Integration tests for parsing + classification flows
- Error Handling: Fix and document RenderBoundary component
- Linting: Fix type issues and update configurations

BREAKING: Requires npm install for new testing dependencies

Author: VrushankPatel

package-lock.json

@@ -22,14 +22,17 @@
     "@eslint/js": "^9.37.0",
     "@playwright/test": "^1.55.0",
     "@tailwindcss/vite": "^4.2.1",
+    "@testing-library/jest-dom": "^6.9.1",
+    "@testing-library/react": "^16.3.2",
     "eslint": "^9.37.0",
     "eslint-plugin-react": "^7.37.5",
     "eslint-plugin-react-hooks": "^5.2.0",
     "globals": "^16.4.0",
+    "jsdom": "^24.1.3",
     "tailwindcss": "^4.2.1",
     "typescript": "^5.9.3",
-    "vitest": "^3.2.4",
-    "vite": "^7.3.1"
+    "vite": "^7.3.1",
+    "vitest": "^3.2.4"
   },
   "dependencies": {
     "@vitejs/plugin-react": "^5.1.4",