refactor: BSP推送提取公共函数 + 清理

- _push_bsp() 提取重复的key构造+推送逻辑
- bsp.klc None防护
- getattr替代hasattr+属性访问
- 修正首轮日志（不再写"不推送"）

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

ChanPivotMonitor.py

@@ -27,7 +27,7 @@ class ChanPivotMonitor:
         self._current_bi_count: int = 0
         self._current_is_sure: bool = False
         self._current_state: Optional[dict] = None
-        self._duration_added_for_zs: set = set()  # 已加入窗口的中枢 ID
+        self._duration_added_for_zs: set = set()  # 已加入窗口的中枢 ID（上限 200）
 
     # ------------------------------------------------------------------
     # Public API
@@ -87,7 +87,7 @@ class ChanPivotMonitor:
             "gg": round(zs.gg, 6),
             "dd": round(zs.dd, 6),
             **features,
-            "start_time": str(zs.start_time) if hasattr(zs, "start_time") and zs.start_time else None,
+            "start_time": str(t) if (t := getattr(zs, "start_time", None)) else None,
         }
 
         # 中枢刚变为已确认时，将其 duration 加入滚动窗口