硬性策略质量门禁 validate_strategy()

新增 STRATEGY_QUALITY_GATES 检查清单（9条红线）：
CRITICAL: 止损/止盈存在+>0, 买入区下沿<上沿
HIGH: 止损≤买入区, 买入推荐含RR≥1.5, 港股标currency=HKD
MEDIUM: signal短词, tech_snapshot含技术位

enforce_strategy_quality() 插在写入链的两处：
1. reassess_with_context() return前 → 单只重评必过
2. regenerate_all() for d in decisions: 写DB前 → 批量重评必过

不过的：status=review_needed, signal降级→信号不充分
不会写进DB/JSON，除非修复了CRITICAL问题

data/stocks/300750.json

@@ -61,6 +61,11 @@
       "content": "长飞光纤光缆(06869) 255.40+6.68%放量大涨，持有等站上成本263.72；腾讯(00700) 429.80+2.28%，买入区435-440依然可加；中芯H(00981) 89.40+",
       "report_id": "cron_99c06255590a_2026-07-01_08-39-42"
     },
+    {
+      "time": "2026-07-02T08:55:30.266659",
+      "content": "- **宁德时代(300750)** 386.45 / 止损362.31 — 买入区间371~381已触发，现价略高，挂单378加仓",
+      "report_id": "cron_99c06255590a_2026-07-02_08-32-48"
+    },
     {
       "time": "2026-06-02T12:55:54.834592",
       "content": "| 宁德时代(300750) | 427.84 | +1.84% | 4.04% | 持有，止损400止盈460 |",