fix: parse_signal 兼容【仓位】字段+unit追踪+减幅计算+跟单建议

【背景】Jasonleo 9次BTC减仓信号，process_signal.py 的 size regex 只匹配【仓位大小】，不匹配【仓位】。导致推信号显示 size='?'，无法算减幅，agent 推减仓建议全错位。

【修复】
1. parse_signal.py:67 - size regex 兼容【仓位(?:大小)?】
2. parse_signal.py:68 - 新增 unit 字段（BTC/USDT/张）
3. parse_signal.py:285 - 推信号时显示 size+unit
4. parse_signal.py:294 - 跟单建议: fetch 真实持仓+算大佬减幅+同比例跟单
5. signal_tracker.py:158 - format_comparison 智能显示整数/小数 + 减幅%

【测试】1450.719 BTC ✅, 49.958（无单位）✅, 10000 USDT ✅
【验证】format_comparison 减幅 -7.1% 显示正确

okx-auto-position/scripts/signal_tracker.py

@@ -155,17 +155,28 @@ def format_comparison(trader, symbol, current_size):
     """格式化对比信息"""
     last_size, desc = compare_position(trader, symbol, current_size)
 
+    # 智能显示: 整数直接显示, 小数保留 2-3 位
+    def _fmt(n):
+        if n is None:
+            return "?"
+        if n == int(n) and abs(n) >= 10:
+            return f"{int(n):,}"
+        return f"{n:,.2f}"
+
     if last_size is None:
-        return f"• {trader} {symbol}: 首次出现，仓位 {current_size:,.0f}"
+        return f"• {trader} {symbol}: 首次出现，仓位 {_fmt(current_size)}"
 
     if "不变" in desc:
-        return f"• {trader} {symbol}: 仓位不变 {current_size:,.0f}"
+        return f"• {trader} {symbol}: 仓位不变 {_fmt(current_size)}"
     elif "加仓" in desc:
-        return f"• 📈 {trader} {symbol}: {last_size:,.0f} → {current_size:,.0f}（{desc}）"
+        return f"• 📈 {trader} {symbol}: {_fmt(last_size)} → {_fmt(current_size)}（{desc}）"
     elif "减仓" in desc:
-        return f"• 📉 {trader} {symbol}: {last_size:,.0f} → {current_size:,.0f}（{desc}）"
+        delta_pct = 0
+        if last_size and last_size > 0:
+            delta_pct = (current_size - last_size) / last_size * 100
+        return f"• 📉 {trader} {symbol}: {_fmt(last_size)} → {_fmt(current_size)}（减幅 {delta_pct:+.1f}%）"
     else:
-        return f"• {trader} {symbol}: {last_size:,.0f} → {current_size:,.0f}（{desc}）"
+        return f"• {trader} {symbol}: {_fmt(last_size)} → {_fmt(current_size)}（{desc}）"
 
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