fix: 优化 SQLite 数据库连接配置，启用 WAL 模式提升并发性能

- 添加连接池参数（pool_size=5, max_overflow=10, pool_pre_ping）
- 设置连接超时（timeout=30）并允许多线程访问（check_same_thread=False）
- 通过 SQLAlchemy event 在每次连接时自动设置 PRAGMA：
  - journal_mode=WAL：支持读写并发，减少锁争用
  - busy_timeout=30000：等待锁释放最多 30 秒
  - synchronous=NORMAL：在性能与数据安全间取得平衡
  - foreign_keys=ON：强制外键约束

Author: TNT-Likely

src/web/database.py

@@ -3,7 +3,7 @@
 import os
 import shutil
 from datetime import datetime
-from sqlalchemy import create_engine, text
+from sqlalchemy import create_engine, event, text
 from sqlalchemy.orm import sessionmaker, DeclarativeBase
 
 from src.web.migrations import has_pending_migrations, run_versioned_migrations
@@ -13,7 +13,29 @@
 DB_PATH = os.path.join(os.path.dirname(__file__), "..", "..", "data", "panwatch.db")
 os.makedirs(os.path.dirname(DB_PATH), exist_ok=True)
 
-engine = create_engine(f"sqlite:///{DB_PATH}", echo=False)
+engine = create_engine(
+    f"sqlite:///{DB_PATH}",
+    echo=False,
+    connect_args={
+        "timeout": 30,
+        "check_same_thread": False,
+    },
+    pool_size=5,
+    max_overflow=10,
+    pool_pre_ping=True,
+)
+
+
+@event.listens_for(engine, "connect")
+def _set_sqlite_pragma(dbapi_conn, connection_record):
+    cursor = dbapi_conn.cursor()
+    cursor.execute("PRAGMA journal_mode=WAL")
+    cursor.execute("PRAGMA busy_timeout=30000")
+    cursor.execute("PRAGMA synchronous=NORMAL")
+    cursor.execute("PRAGMA foreign_keys=ON")
+    cursor.close()
+
+
 SessionLocal = sessionmaker(bind=engine)