fix: NOFXi Agent real AI integration + quality improvements

Critical fixes:
1. Agent now uses NOFX's MCP client for AI calls (real models, not placeholder)
   - Gets AI client from first configured trader's MCP config
   - Added AutoTrader.GetMCPClient() export
2. /analyze uses REAL market data (market.Get → EMA/MACD/RSI/BB/OI/funding)
   then sends to AI — no more hallucinated prices
3. AI chat enriches prompts with live market data when user mentions a coin
4. Fallback: if AI unavailable, shows raw formatted market data (still useful)

Router improvements:
- Better natural language detection for Chinese
- '该不该买' '走势' '趋势' '行情' → analyze intent
- '多少钱' '赚了' '亏了' → query intent
- Fewer messages falling through to generic chat

Web UI:
- Endpoints updated to /api/agent/* namespace
- nofxi.html served at agent root (localhost:8900)

Result: AI analysis now shows real BTC price, real RSI, real EMA — not fiction.

main.go

@@ -145,6 +145,16 @@ func main() {
 
 	// Start NOFXi Agent (proactive intelligence layer)
 	nofxiAgent := nofxiagent.New(traderManager, st, nil, slog.Default())
+
+	// Try to get an AI client from existing trader configs
+	for _, t := range traderManager.GetAllTraders() {
+		if mcpClient := t.GetMCPClient(); mcpClient != nil {
+			nofxiAgent.SetAIClient(mcpClient)
+			logger.Info("🧠 NOFXi Agent using AI model from trader", "trader", t.GetName())
+			break
+		}
+	}
+
 	nofxiAgent.Start()
 	defer nofxiAgent.Stop()