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/src/api/client.ts

@@ -0,0 +1,15 @@
+// In production the browser hits /api/* and Nginx strips the prefix.
+// In dev, Vite's proxy does the same stripping.
+// So we always use /api/ as prefix — works both environments.
+const API_BASE = '/api';
+
+export async function apiFetch<T>(path: string): Promise<T> {
+  const res = await fetch(`${API_BASE}${path}`, { credentials: 'include' });
+  if (!res.ok) throw new Error(`API ${path}: ${res.status}`);
+  return res.json();
+}
+
+export function wsUrl(): string {
+  const proto = location.protocol === 'https:' ? 'wss:' : 'ws:';
+  return `${proto}//${location.host}/api/ws/live`;
+}

frontend/src/api/endpoints.ts

@@ -0,0 +1,22 @@
+import { apiFetch } from './client';
+import type { TelemetrySnapshot, CombatStatsMessage, ServerHealth } from '../types';
+
+interface LiveResponse {
+  players: TelemetrySnapshot[];
+}
+
+interface CombatStatsResponse {
+  stats: CombatStatsMessage[];
+}
+
+interface CountResponse {
+  total_rares?: number;
+  total_kills?: number;
+  count?: number;
+}
+
+export const getLive = () => apiFetch<LiveResponse>('/live');
+export const getCombatStats = () => apiFetch<CombatStatsResponse>('/combat-stats');
+export const getServerHealth = () => apiFetch<ServerHealth>('/server-health');
+export const getTotalRares = () => apiFetch<CountResponse>('/total-rares');
+export const getTotalKills = () => apiFetch<CountResponse>('/total-kills');