完全DB版: 移除JSON写入/回退，所有操作直走SQLite

- price_monitor: 完全DB版，不再读写 portfolio.json/watchlist.json
  - holdings代码从DB读取（SELECT code FROM holdings WHERE is_active=1）
  - 价格写入DB holdings表 + portfolio_summary + live_prices
  - 3次重试+指数退避防锁
- server.py: 移除API的JSON回退，DB失败直接返回500
- mofin_db.py: execute_with_retry/commit_with_retry + 15s timeout + busy_timeout
- mo_data.py: 已是纯DB模式（无JSON fallback）

这是推进的完全DB化。下一步可删除 data/portfolio.json data/decisions.json data/watchlist.json 等遗留JSON。

price_monitor.py

@@ -100,77 +100,45 @@ def fetch_all_prices(codes):
 
 
 def refresh_data_prices():
-    """一次性刷新portfolio.json和watchlist.json的所有实时价"""
+    """一次性刷新所有持仓+自选股的实时价（完全DB版，不写JSON）"""
     all_codes = set()
 
-    # 收集所有需要拉取的代码
+    # 从DB读所有需要拉取价格的代码
     try:
-        pf = json.load(open(PORTFOLIO_PATH))
-        for s in pf.get('holdings', []):
-            all_codes.add(s['code'])
-    except:
-        pf = {"holdings": []}
-
-    try:
-        wl = json.load(open(WATCHLIST_PATH))
-        for s in wl.get('stocks', []):
-            all_codes.add(s['code'])
-    except:
-        wl = {"stocks": []}
+        conn = get_conn()
+        for r in conn.execute("SELECT code FROM holdings WHERE is_active=1"):
+            all_codes.add(r['code'])
+        for r in conn.execute("SELECT code FROM watchlist_stocks"):
+            all_codes.add(r['code'])
+        conn.close()
+    except Exception as e:
+        print(f"⚠️ 从DB读代码失败: {e}", file=sys.stderr)
+        return 0
 
     if not all_codes:
         return 0
 
     # 一次性批量拉取
     prices = fetch_all_prices(list(all_codes))
-    updated = 0
-
-    # 更新portfolio（只在价格变化时写入，避免触发文件变更通知）
-    changed = False
-    for s in pf.get('holdings', []):
-        if s['code'] in prices:
-            price, _, change_pct = prices[s['code']]
-            if price > 0:
-                old = s.get('price', 0)
-                if abs(old - price) > 0.001:
-                    s['price'] = round(price, 2)
-                    s['change_pct'] = float(change_pct) if change_pct else 0
-                    updated += 1
-                    changed = True
-    if changed:
-        json.dump(pf, open(PORTFOLIO_PATH, 'w'), ensure_ascii=False, indent=2)
-
-    # 更新watchlist（只在价格变化时写入）
-    changed = False
-    for s in wl.get('stocks', []):
-        if s['code'] in prices:
-            price, _, change_pct = prices[s['code']]
-            if price > 0:
-                old = s.get('price', 0)
-                if abs(old - price) > 0.001:
-                    s['price'] = round(price, 2)
-                    s['change_pct'] = float(change_pct) if change_pct else 0
-                    updated += 1
-                    changed = True
-    if changed:
-        wl['updated_at'] = datetime.now().isoformat()
-        json.dump(wl, open(WATCHLIST_PATH, 'w'), ensure_ascii=False, indent=2)
+    updated = len(prices)
 
     # === 同步实时价到 mofin.db（带重试防锁） ===
     if HAS_DB and prices:
         for db_attempt in range(3):
             try:
                 conn = get_conn()
-                # 直接从 portfolio.json 构建更新数据（保留已有的 market_value/currency）
+
+                # 构建 holdings 更新数据
                 db_holdings = []
-                for s in pf.get('holdings', []):
-                    code = str(s.get('code', ''))
+                for r in conn.execute("SELECT * FROM holdings WHERE is_active=1"):
+                    h = dict(r)
+                    code = str(h.get('code', ''))
                     if code in prices:
                         price_val, _, change_pct = prices[code]
                         if price_val > 0:
-                            s['price'] = round(price_val, 2)
-                            s['change_pct'] = float(change_pct) if change_pct else 0
-                    db_holdings.append(s)
+                            h['price'] = round(price_val, 2)
+                            h['change_pct'] = float(change_pct) if change_pct else 0
+                    db_holdings.append(h)
 
                 # 写入DB持仓价格（write_holdings_batch 用 ON CONFLICT UPDATE 只改价格字段）
                 ok, msg = write_holdings_batch(conn, db_holdings)