总资产公式修复+数据模型文档

bugfix: price_monitor写total_assets时漏算frozen_cash
  公式修正: total_assets = market_value + cash + frozen_cash
  影响: price_monitor两处公式 + stale_push_wlin fallback路径

docs: portfolio-data-model.md 新增
  数据模型字段说明
  现金流更新规则
  常见错误清单

data/portfolio.json

@@ -651,15 +651,15 @@
   ],
   "cash": 92678.85,
   "total_market_value": 835552.6,
-  "total_assets": 928231.45,
+  "total_assets": 967712.85,
   "total_pl": 0,
   "position_pct": 90.02,
-  "updated_at": "2026-06-29 22:23:47",
+  "updated_at": "2026-06-29 22:28",
   "source": "/home/hmo/stocks/holding.xls",
   "frozen_cash": 39481.4,
   "available_cash": 92678.85,
   "frozen": 39481.4,
-  "total_cash": 132145.6,
+  "total_cash": 132160.25,
   "cash_updated_at": "2026-06-29 12:34",
   "recent_trades": [
     {
@@ -675,10 +675,10 @@
   "total_mv": 835552.6,
   "note": "cash fixed from screenshot 6/29, prices=CNY",
   "currency": "CNY",
-  "last_verified_at": "2026-06-29 22:20",
+  "last_verified_at": "2026-06-29 22:28",
   "_total_mv": 835552.6,
-  "_total_cash": 113240.25,
-  "_total_assets": 948792.85,
+  "_total_cash": 132160.25,
+  "_total_assets": 967712.85,
   "cash_history": [
     {
       "time": "2026-06-29 22:23:47",
@@ -686,6 +686,14 @@
       "frozen": 39481.4,
       "source": "manual:post-法拉电子-sell-100shares@189.2",
       "formula": "初始可用73758.85+法拉电子18920"
+    },
+    {
+      "time": "2026-06-29 22:28",
+      "cash": 92678.85,
+      "frozen": 39481.4,
+      "total_mv": 835552.6,
+      "total_assets": 967712.85,
+      "source": "price_monitor_auto"
     }
   ]
 }