进一步修复 SQLite 并发锁冲突，统一连接与重试机制。

新增 db_conn 模块、缓存 schema 初始化、positions 页 commit，风控读库自动重试。

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

app.py

@@ -34,6 +34,7 @@ from kline_store import ensure_kline_tables
 from kline_stream import kline_hub, sse_format
 from kline_chart import generate_review_kline_chart, fetch_market_klines, MARKET_PERIODS
 from market import get_price as market_get_price, set_ths_refresh_token, get_quote_source_label
+from db_conn import connect_db
 from strategy.strategy_db import init_strategy_tables
 from install_trading import install_trading
 from vnpy_bridge import try_init_vnpy
@@ -155,17 +156,9 @@ def expire_old_plans():
     conn.commit()
     conn.close()
 
-# —————————————— 设置读写 ——————————————
 
 def get_db():
-    conn = sqlite3.connect(DB_PATH, timeout=30)
-    conn.row_factory = sqlite3.Row
-    conn.execute("PRAGMA busy_timeout=30000")
-    try:
-        conn.execute("PRAGMA journal_mode=WAL")
-    except sqlite3.OperationalError:
-        pass
-    return conn
+    return connect_db()
 
 
 def get_setting(key: str, default: str = "") -> str:
@@ -315,6 +308,8 @@ def init_db():
                   updated_at TEXT NOT NULL)''')
     ensure_kline_tables(conn)
     init_strategy_tables(conn)
+    from risk.account_risk_lib import ensure_account_risk_schema
+    ensure_account_risk_schema(conn)
     conn.commit()
     conn.close()