feat: add per-account daily open hard limit across all exchanges

Enforce optional DAILY_OPEN_HARD_LIMIT in precheck_risk and can_trade, keep AI alerts at DAILY_OPEN_ALERT_THRESHOLD, and document env setup for all four instances.

Co-authored-by: Cursor <cursoragent@cursor.com>

crypto_monitor_okx/.env.example

@@ -140,7 +140,7 @@ AI_MODEL=huihui_ai/deepseek-r1-abliterated:latest
 # ORDER_CHART_TFS=4h,1h,15m,5m
 # ORDER_CHART_LIMIT=100
 # ORDER_CHART_DIR=static/images/order_charts
-# DAILY_OPEN_ALERT_THRESHOLD=5
+# 详见 DAILY_OPEN_ALERT_THRESHOLD / DAILY_OPEN_HARD_LIMIT；说明文档 docs/daily-open-limit.md
 # 关键位：标准方案止损外侧%、趋势单方案止损外侧%（默认 0.5 / 1）
 # KEY_STOP_OUTSIDE_BREAKOUT_PCT=0.5
 # KEY_TREND_STOP_OUTSIDE_PCT=1
@@ -162,6 +162,10 @@ TRADING_DAY_RESET_OPEN_GUARD_ENABLED=true
 
 MAX_ACTIVE_POSITIONS=1
 MANUAL_MIN_PLANNED_RR=1.4
+# 【单日开仓 AI 提醒】本交易日开仓达到该次数时推送企业微信 AI 克制提醒（不拦单）
+DAILY_OPEN_ALERT_THRESHOLD=5
+# 【单日开仓硬上限】本交易日开仓次数>=该值后禁止一切新开仓直至下一交易日（北京时间 TRADING_DAY_RESET_HOUR 切日）；0=不启用
+DAILY_OPEN_HARD_LIMIT=0
 
 KEY_CONFIRM_BREAKOUT_BAR=-2
 KEY_CONFIRM_BAR=-1