feat(nofxi): proactive intelligence - Sentinel, Brain, Learner

🧠 Brain (proactive intelligence):
- Receives signals from Sentinel and decides when to notify
- Signal debouncing (same type+symbol within 10min)
- Morning brief at 08:30, evening brief at 20:30 (AI-generated)
- Crypto news scanning every 5 minutes
- Auto-filters high-impact news by sentiment + relevance

👁️ Sentinel (market anomaly detection):
- Watches BTC/ETH/SOL by default (expandable)
- Price breakout detection (>3% in 5 minutes)
- Volume spike detection (>3x average)
- Funding rate anomaly detection (>0.1%)
- 60-second scan interval, 1-hour price history buffer

📰 News Monitor:
- CryptoCompare API (free, no auth)
- Keyword-based sentiment classification (bullish/bearish/neutral)
- Symbol extraction from headlines
- Deduplication via seen URLs

📚 Learner (trading memory):
- User profile analysis (win rate, preferred side, risk tolerance)
- Trading lessons storage (win/loss patterns, strategy notes)
- AI prediction tracking (log predictions → resolve with actual P/L)
- Prediction accuracy metrics per model

NOFXi is no longer a passive chatbot. It watches, thinks, learns, and acts.

nofxi/internal/agent/brain.go

@@ -0,0 +1,189 @@
+package agent
+
+import (
+	"context"
+	"fmt"
+	"log/slog"
+	"strings"
+	"time"
+
+	"nofx/nofxi/internal/perception"
+	"nofx/nofxi/internal/thinking"
+)
+
+// Brain is the proactive intelligence layer.
+// It receives signals from Sentinel, processes news, and decides
+// when to proactively notify the user.
+type Brain struct {
+	agent       *Agent
+	news        *perception.NewsMonitor
+	logger      *slog.Logger
+	stopCh      chan struct{}
+
+	// Debounce: don't spam the same signal
+	recentSignals map[string]time.Time
+}
+
+// NewBrain creates the proactive brain.
+func NewBrain(agent *Agent, logger *slog.Logger) *Brain {
+	return &Brain{
+		agent:         agent,
+		news:          perception.NewNewsMonitor(logger),
+		logger:        logger,
+		stopCh:        make(chan struct{}),
+		recentSignals: make(map[string]time.Time),
+	}
+}
+
+// HandleSignal processes a market signal from the Sentinel.
+func (b *Brain) HandleSignal(signal perception.Signal) {
+	// Debounce: same signal type + symbol within 10 minutes
+	key := fmt.Sprintf("%s:%s", signal.Type, signal.Symbol)
+	if last, ok := b.recentSignals[key]; ok && time.Since(last) < 10*time.Minute {
+		return
+	}
+	b.recentSignals[key] = time.Now()
+
+	// Format alert message
+	emoji := map[string]string{
+		"info":     "ℹ️",
+		"warning":  "⚠️",
+		"critical": "🚨",
+	}
+	e := emoji[signal.Severity]
+	if e == "" {
+		e = "📊"
+	}
+
+	msg := fmt.Sprintf("%s *%s*\n\n%s\n\n_%s_",
+		e, signal.Title, signal.Detail, signal.Timestamp.Format("15:04:05"))
+
+	b.notifyAll(msg)
+}
+
+// StartNewsScan begins periodic news scanning.
+func (b *Brain) StartNewsScan(interval time.Duration) {
+	go func() {
+		ticker := time.NewTicker(interval)
+		defer ticker.Stop()
+
+		for {
+			select {
+			case <-b.stopCh:
+				return
+			case <-ticker.C:
+				b.scanNews()
+			}
+		}
+	}()
+}
+
+// StartMarketBrief sends a morning/evening market brief.
+func (b *Brain) StartMarketBrief() {
+	go func() {
+		ticker := time.NewTicker(1 * time.Minute)
+		defer ticker.Stop()
+
+		for {
+			select {
+			case <-b.stopCh:
+				return
+			case now := <-ticker.C:
+				hour := now.Hour()
+				minute := now.Minute()
+
+				// Morning brief at 08:30
+				if hour == 8 && minute == 30 {
+					b.sendMarketBrief("morning")
+				}
+				// Evening brief at 20:30
+				if hour == 20 && minute == 30 {
+					b.sendMarketBrief("evening")
+				}
+			}
+		}
+	}()
+}
+
+func (b *Brain) scanNews() {
+	items, err := b.news.FetchNews()
+	if err != nil {
+		b.logger.Error("fetch news", "error", err)
+		return
+	}
+
+	// Filter for high-impact news related to watched symbols
+	for _, item := range items {
+		if item.Sentiment == "neutral" {
+			continue
+		}
+		if len(item.Symbols) == 0 {
+			continue
+		}
+		// Only alert on recent news (last 10 minutes)
+		if time.Since(item.Timestamp) > 10*time.Minute {
+			continue
+		}
+
+		emoji := "📰"
+		if item.Sentiment == "bullish" {
+			emoji = "🟢"
+		} else if item.Sentiment == "bearish" {
+			emoji = "🔴"
+		}
+
+		msg := fmt.Sprintf("%s *%s*\n\n%s\n\n• Source: %s\n• Symbols: %s\n• Sentiment: %s",
+			emoji, "News Alert",
+			item.Title,
+			item.Source,
+			strings.Join(item.Symbols, ", "),
+			strings.ToUpper(item.Sentiment),
+		)
+		b.notifyAll(msg)
+	}
+}
+
+func (b *Brain) sendMarketBrief(timeOfDay string) {
+	ctx, cancel := context.WithTimeout(context.Background(), 30*time.Second)
+	defer cancel()
+
+	prompt := fmt.Sprintf(`Generate a brief %s market summary for crypto trading.
+Include: BTC/ETH price direction, key levels, market sentiment, any notable events.
+Be concise (under 200 words). Use trading emojis. Respond in Chinese.
+Current time: %s`, timeOfDay, time.Now().Format("2006-01-02 15:04:05"))
+
+	resp, err := b.agent.thinker.Chat(ctx, []thinking.Message{
+		{Role: "system", Content: "You are NOFXi, a professional crypto trading AI. Respond in Chinese."},
+		{Role: "user", Content: prompt},
+	})
+	if err != nil {
+		b.logger.Error("generate market brief", "error", err)
+		return
+	}
+
+	title := "☀️ *早间市场简报*"
+	if timeOfDay == "evening" {
+		title = "🌙 *晚间市场简报*"
+	}
+
+	msg := fmt.Sprintf("%s\n\n%s\n\n_Generated by NOFXi 🤖_", title, resp)
+	b.notifyAll(msg)
+}
+
+func (b *Brain) notifyAll(text string) {
+	if b.agent.NotifyFunc == nil {
+		return
+	}
+	for _, uid := range b.agent.config.Telegram.AllowedIDs {
+		if err := b.agent.NotifyFunc(uid, text); err != nil {
+			b.logger.Error("notify", "user_id", uid, "error", err)
+		}
+	}
+}
+
+// Stop stops the brain.
+func (b *Brain) Stop() {
+	close(b.stopCh)
+}
+
+