feat: init nofxi - AI Trading Agent module

NOFXi — Your AI Trading Agent, built on NOFX.

Architecture:
- Agent Core: intent routing, conversation memory, trade confirmation
- Memory: SQLite (trades, conversations, preferences, strategies)
- Thinking: LLM client (OpenAI/claw402/DeepSeek compatible)
- Execution: Bridge to NOFX trader engine (9 exchanges)
- Perception: Market monitor, price alerts, anomaly detection
- Interaction: Telegram bot + REST API + OpenAI-compatible endpoint

Features:
- Natural language trading (中英文)
- /buy /sell /analyze /watch /alert /positions /balance
- Daily P/L reports, portfolio risk checks
- Trade confirmation flow (safety first)
- Price polling and alert notifications

nofxi/internal/interaction/formatter.go

@@ -0,0 +1,68 @@
+package interaction
+
+import (
+	"fmt"
+	"strings"
+	"time"
+)
+
+// FormatTradeAlert formats a trade event for Telegram notification.
+func FormatTradeAlert(action, symbol, exchange string, price, quantity float64) string {
+	emoji := "🟢"
+	if action == "sell" || action == "short" || action == "close" {
+		emoji = "🔴"
+	}
+	return fmt.Sprintf(`%s *Trade Executed*
+
+• Action: %s
+• Symbol: %s
+• Exchange: %s
+• Price: $%.4f
+• Quantity: %.6f
+• Value: $%.2f
+• Time: %s`,
+		emoji,
+		strings.ToUpper(action),
+		symbol,
+		exchange,
+		price,
+		quantity,
+		price*quantity,
+		time.Now().Format("15:04:05"),
+	)
+}
+
+// FormatDailyReport formats a daily P/L summary.
+func FormatDailyReport(totalPnL float64, trades int, winRate float64) string {
+	emoji := "📈"
+	if totalPnL < 0 {
+		emoji = "📉"
+	}
+	return fmt.Sprintf(`%s *Daily Report — %s*
+
+• Trades: %d
+• Win Rate: %.1f%%
+• P/L: $%.2f
+
+Keep going! 💪`,
+		emoji,
+		time.Now().Format("2006-01-02"),
+		trades,
+		winRate,
+		totalPnL,
+	)
+}
+
+// FormatPriceAlert formats a price alert notification.
+func FormatPriceAlert(symbol string, price float64, direction string, threshold float64) string {
+	emoji := "🚨"
+	if direction == "above" {
+		emoji = "📈"
+	} else {
+		emoji = "📉"
+	}
+	return fmt.Sprintf(`%s *Price Alert*
+
+%s hit $%.4f (%s $%.4f threshold)`,
+		emoji, symbol, price, direction, threshold)
+}