fix(dashboard): rewrite topology graph for performance at scale

Replaced React state-driven animation with ECharts graph rendering.
Previous approach re-rendered 263+ SVG nodes via setState in rAF loop,
causing browser lockup. New approach uses ECharts which handles force
layout and rendering natively at scale.

Changes:
- Switch from D3 force sim + React state to ECharts graph
- Remove particle animation (was fake random noise, not real packets)
- Filter out nodes with zero edges by default
- Add filter controls: Connected, Infra, All
- ECharts handles zoom/pan/drag natively (roam: true)
- Node selection dims unrelated nodes
- Force config matches Meshview: repulsion 200, edgeLength [80,120]
- Animation disabled for performance (animation: false)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

dashboard-frontend/package.json

@@ -9,20 +9,27 @@
     "preview": "vite preview"
   },
   "dependencies": {
+    "@types/d3": "^7.4.3",
+    "@types/leaflet": "^1.9.21",
+    "d3": "^7.9.0",
+    "echarts": "^6.0.0",
+    "echarts-for-react": "^3.0.6",
+    "leaflet": "^1.9.4",
+    "lucide-react": "^0.383.0",
     "react": "^18.3.0",
     "react-dom": "^18.3.0",
+    "react-leaflet": "^4.2.1",
     "react-router-dom": "^6.23.0",
-    "recharts": "^2.12.0",
-    "lucide-react": "^0.383.0"
+    "recharts": "^2.12.0"
   },
   "devDependencies": {
     "@types/react": "^18.3.0",
     "@types/react-dom": "^18.3.0",
     "@vitejs/plugin-react": "^4.3.0",
-    "typescript": "^5.4.0",
-    "vite": "^5.4.0",
-    "tailwindcss": "^3.4.0",
+    "autoprefixer": "^10.4.0",
     "postcss": "^8.4.0",
-    "autoprefixer": "^10.4.0"
+    "tailwindcss": "^3.4.0",
+    "typescript": "^5.4.0",
+    "vite": "^5.4.0"
   }
 }