feat: Implement a thread-safe account store with pool management, CRUD operations, and statistics tracking.

core/account_store.py

@@ -8,8 +8,9 @@ import json
 import threading
 from pathlib import Path
 
-_ACCOUNTS_FILE = Path(__file__).parent / "accounts.txt"
-_STATS_FILE = Path(__file__).parent / "stats.json"
+_PROJECT_ROOT = Path(__file__).parent.parent
+_ACCOUNTS_FILE = _PROJECT_ROOT / "accounts.txt"
+_STATS_FILE = _PROJECT_ROOT / "stats.json"
 _lock = threading.Lock()
 
 # ====== 账号池（并发调度）======