feat: v2 dashboard — React + Vite parallel implementation

New modern dashboard at /v2 running alongside the existing UI at /.
Same backend, same APIs, same WebSocket — zero backend changes.

Stack: React 19 + Vite + TypeScript + Recharts
Source: frontend/ — build output: static/v2/

Phase 1 delivers:
- Character overview cards in a responsive CSS Grid
  - Live HP/Stamina/Mana bars via WebSocket vitals
  - Kills/hr, total kills, deaths, session uptime
  - VTank state badge (Combat/Nav/Idle)
  - Location coordinates
  - Click to expand: combat stats, prismatic count, CPU/RAM
- Global stats header: active chars, total kills, total rares, server health
- WebSocket hook with auto-reconnect
- HTTP poll fallback for initial load + server health
- Mobile responsive (single column on narrow screens)
- Dark theme matching the MosswartOverlord palette

Build: cd frontend && npm run build
Access: /v2 (served by existing NoCacheStaticFiles mount)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

frontend/package.json

@@ -0,0 +1,23 @@
+{
+  "name": "mosswart-overlord-v2",
+  "private": true,
+  "version": "0.1.0",
+  "type": "module",
+  "scripts": {
+    "dev": "vite",
+    "build": "tsc -b && vite build",
+    "preview": "vite preview"
+  },
+  "dependencies": {
+    "react": "^19.1.0",
+    "react-dom": "^19.1.0",
+    "recharts": "^2.15.3"
+  },
+  "devDependencies": {
+    "@types/react": "^19.1.2",
+    "@types/react-dom": "^19.1.2",
+    "@vitejs/plugin-react": "^4.4.1",
+    "typescript": "~5.8.3",
+    "vite": "^6.3.3"
+  }
+}