refactor: 数据层重构 — 统一 SQLite 访问层 + 多脚本双写

新建 mofin_db.py 共享数据库模块:
- get_conn() 统一连接管理 (WAL + Row factory + 外键)
- init_all_tables() 幂等建表 (12张表: market/sector/stock/kline/fundamentals/sectors/holdings/strategies/watchlist/candidates/score_history/events/evaluations)
- write_market_snapshot() 市场快照双写
- write_klines() K线数据双写 (stocks + daily/weekly/monthly + fundamentals)
- write_price_event() 价格事件双写
- migrate_stock_sectors() 一次性迁移 stock_sector_map.json
- query_*() 通用查询函数 (sector_trend/top_inflow/consecutive_inflow/market_mood/db_stats)

重构现有脚本:
- market_watch.py: 删除内联 DB 代码，改用 mofin_db
- multi_timeframe.py: _save_local_history() 加 SQLite 双写
- price_monitor.py: record_event() 加 SQLite 双写
- mofin_query.py: 改用 mofin_db 查询函数

新增:
- migrate_sectors.py: 一次性迁移脚本

清理:
- get_realtime_prices.py: 死代码 (只读 portfolio.json，不调API)

market_watch.py

@@ -13,102 +13,12 @@
 """
 
 import json
-import sqlite3
 from datetime import datetime
 from pathlib import Path
 
+from mofin_db import get_conn, init_all_tables, write_market_snapshot
+
 DATA_DIR = Path(__file__).parent / "data"
-DB_PATH = DATA_DIR / "mofin.db"
-
-# ── 数据库初始化 ──────────────────────────────────────
-
-def init_db():
-    """创建 mofin.db 及所有表（幂等，已存在则跳过）"""
-    DATA_DIR.mkdir(parents=True, exist_ok=True)
-    conn = sqlite3.connect(str(DB_PATH))
-    conn.execute("PRAGMA journal_mode=WAL")
-    conn.execute("PRAGMA foreign_keys=ON")
-    conn.executescript("""
-        CREATE TABLE IF NOT EXISTS market_snapshots (
-            id          INTEGER PRIMARY KEY AUTOINCREMENT,
-            timestamp   TEXT    NOT NULL,
-            source      TEXT    NOT NULL DEFAULT 'ths',
-            up_ratio    REAL,
-            mood        TEXT,
-            created_at  TEXT    DEFAULT (datetime('now','localtime'))
-        );
-        CREATE INDEX IF NOT EXISTS idx_snapshots_time ON market_snapshots(timestamp);
-
-        CREATE TABLE IF NOT EXISTS sector_snapshots (
-            id              INTEGER PRIMARY KEY AUTOINCREMENT,
-            snapshot_id     INTEGER NOT NULL REFERENCES market_snapshots(id),
-            name            TEXT    NOT NULL,
-            change_pct      REAL,
-            up_count        INTEGER,
-            down_count      INTEGER,
-            net_inflow      REAL,
-            lead_stock      TEXT,
-            lead_stock_change REAL,
-            volume          REAL,
-            turnover        REAL
-        );
-        CREATE INDEX IF NOT EXISTS idx_sector_name ON sector_snapshots(name);
-        CREATE INDEX IF NOT EXISTS idx_sector_snapshot ON sector_snapshots(snapshot_id);
-        CREATE INDEX IF NOT EXISTS idx_sector_name_time ON sector_snapshots(name, snapshot_id);
-    """)
-    conn.commit()
-    return conn
-
-
-def write_snapshot(conn, market_data: dict):
-    """将一次采集结果双写 SQLite（JSON 写入由 main 负责）"""
-    try:
-        # 1. INSERT market_snapshots
-        cur = conn.execute(
-            """INSERT INTO market_snapshots (timestamp, source, up_ratio, mood)
-               VALUES (?, ?, ?, ?)""",
-            (
-                market_data["timestamp"],
-                market_data.get("source", "unknown"),
-                market_data.get("up_ratio", 0),
-                market_data.get("mood", "unknown"),
-            ),
-        )
-        snapshot_id = cur.lastrowid
-
-        # 2. INSERT sector_snapshots（逐板块）
-        sectors = market_data.get("sectors", [])
-        rows = []
-        for s in sectors:
-            rows.append((
-                snapshot_id,
-                s.get("name", ""),
-                s.get("change", 0),
-                s.get("up_count"),
-                s.get("down_count"),
-                s.get("net_inflow"),
-                s.get("lead_stock"),
-                s.get("lead_stock_change"),
-                s.get("volume"),
-                s.get("turnover"),
-            ))
-        if rows:
-            conn.executemany(
-                """INSERT INTO sector_snapshots
-                   (snapshot_id, name, change_pct, up_count, down_count,
-                    net_inflow, lead_stock, lead_stock_change, volume, turnover)
-                   VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?)""",
-                rows,
-            )
-        conn.commit()
-        return snapshot_id, len(rows)
-    except Exception as e:
-        print(f"[DB] SQLite 写入失败（JSON 不受影响）: {e}", flush=True)
-        try:
-            conn.rollback()
-        except Exception:
-            pass
-        return None, 0
 
 
 # ── 後端A：東方財富 push2 API（首選，有板塊代碼+實時指數） ──
@@ -252,10 +162,13 @@ def main():
         json.dump(market_data, f, ensure_ascii=False, indent=2)
 
     # ── SQLite 双写 ──
-    conn = init_db()
-    sid, count = write_snapshot(conn, market_data)
-    if sid:
-        print(f"[DB] snapshot_id={sid}, sectors={count}", flush=True)
+    conn = get_conn()
+    init_all_tables(conn)
+    ok, msg, sid = write_market_snapshot(conn, market_data)
+    if ok:
+        print(f"[DB] {msg}", flush=True)
+    else:
+        print(f"[DB] 写入失败（JSON 不受影响）: {msg}", flush=True)
     conn.close()
 
     # 靜默：只寫文件，不輸出到stdout，避免cron推送