price_monitor港股币种修复+calc_total_mv汇兑处理

问题链：
  price_monitor 从东方财富/腾讯拿HK股价(HKD) → x0.87转CNY写portfolio
  → DB存CNY→下游混读→建滔显示-24%浮亏（实为-0.6%）
修复：
  price_monitor不转CNY，港股存HKD原值
  calc_total_mv()增加币种判断：HK股用get_hk_rate()转CNY再汇总
  portfolio.json/watchlist的HK股价全部HKD原值
  DB同步修正所有HK股价格为HKD
  price_monitor DB写入加3次重试+database locked timeout
验证：
  建滔 87.7 HKD 浮亏-0.6%（不是-24%）
  现金 132,121.93 总资产 956,714.68

data/price_history.json

@@ -26,7 +26,7 @@
       "date": "2026-07-03",
       "high": 1215.52,
       "low": 1190.51,
-      "close": 1200.55
+      "close": 1201.38
     }
   ],
   "02202": [
@@ -48,7 +48,7 @@
       "date": "2026-07-03",
       "high": 53.0,
       "low": 51.7,
-      "close": 52.55
+      "close": 52.4
     }
   ],
   "601318": [
@@ -62,7 +62,7 @@
       "date": "2026-07-03",
       "high": 50.2,
       "low": 48.8,
-      "close": 48.99
+      "close": 49.05
     }
   ],
   "02359": [
@@ -76,7 +76,7 @@
       "date": "2026-07-03",
       "high": 158.7,
       "low": 151.1,
-      "close": 153.0
+      "close": 152.8
     }
   ],
   "02388": [
@@ -90,7 +90,7 @@
       "date": "2026-07-03",
       "high": 42.98,
       "low": 41.94,
-      "close": 42.76
+      "close": 42.7
     }
   ],
   "02628": [
@@ -104,7 +104,7 @@
       "date": "2026-07-03",
       "high": 29.08,
       "low": 27.5,
-      "close": 28.56
+      "close": 28.58
     }
   ],
   "688630": [
@@ -118,7 +118,7 @@
       "date": "2026-07-03",
       "high": 499.95,
       "low": 444.55,
-      "close": 486.52
+      "close": 486.69
     }
   ],
   "06160": [
@@ -130,9 +130,9 @@
     },
     {
       "date": "2026-07-03",
-      "high": 183.8,
+      "high": 183.9,
       "low": 171.9,
-      "close": 182.1
+      "close": 182.5
     }
   ],
   "06869": [
@@ -154,7 +154,7 @@
       "date": "2026-07-03",
       "high": 687.04,
       "low": 633.01,
-      "close": 645.0
+      "close": 642.05
     }
   ],
   "09868": [
@@ -168,7 +168,7 @@
       "date": "2026-07-03",
       "high": 53.7,
       "low": 49.3,
-      "close": 50.8
+      "close": 50.5
     }
   ],
   "09988": [
@@ -182,7 +182,7 @@
       "date": "2026-07-03",
       "high": 97.4,
       "low": 93.55,
-      "close": 95.65
+      "close": 95.35
     }
   ],
   "688802": [
@@ -196,7 +196,7 @@
       "date": "2026-07-03",
       "high": 733.99,
       "low": 713.0,
-      "close": 724.96
+      "close": 719.01
     }
   ],
   "300124": [
@@ -210,7 +210,7 @@
       "date": "2026-07-03",
       "high": 71.79,
       "low": 67.31,
-      "close": 71.29
+      "close": 71.42
     }
   ],
   "000657": [
@@ -223,8 +223,8 @@
     {
       "date": "2026-07-03",
       "high": 101.5,
-      "low": 88.23,
-      "close": 89.1
+      "low": 87.92,
+      "close": 88.72
     }
   ],
   "000711": [
@@ -252,7 +252,7 @@
       "date": "2026-07-03",
       "high": 872.83,
       "low": 795.0,
-      "close": 843.79
+      "close": 841.41
     }
   ],
   "002594": [
@@ -266,7 +266,7 @@
       "date": "2026-07-03",
       "high": 87.28,
       "low": 81.9,
-      "close": 86.74
+      "close": 86.91
     }
   ],
   "00700": [
@@ -310,7 +310,7 @@
       "date": "2026-07-03",
       "high": 13.19,
       "low": 12.63,
-      "close": 13.12
+      "close": 13.13
     }
   ],
   "01088": [