refactor: remove duplicate scripts + JSON constants + update docs

scripts/import_holding_xls.py

@@ -19,7 +19,6 @@ from mo_data import read_decisions
 from mofin_db import get_conn, write_holdings_batch, write_portfolio_summary, write_holding_strategy
 
 STOCKS_FILE = "/home/hmo/stocks/holding.xls"
-PORTFOLIO_PATH = "/home/hmo/web-dashboard/data/portfolio.json"
 DB_PATH = "/home/hmo/web-dashboard/data/mofin.db"
 
 
@@ -151,9 +150,6 @@ def main():
         'updated_at': datetime.now().strftime('%Y-%m-%d %H:%M'),
         'source': STOCKS_FILE,
     }
-    # [migrated to DB] — cold backup removed; DB writes below
-    # with open(PORTFOLIO_PATH, 'w') as f:
-    #     json.dump(portfolio, f, indent=2, ensure_ascii=False)
     # DB 写入
     try:
         conn = get_conn()