fix: 修复多worker并发初始化时默认管理员唯一键冲突

server/db.py

@@ -62,6 +62,7 @@ def get_db():
     conn = sqlite3.connect(DB_PATH)
     conn.row_factory = sqlite3.Row
     conn.execute("PRAGMA foreign_keys = ON")
+    conn.execute("PRAGMA busy_timeout = 5000")
     return conn
 
 
@@ -70,15 +71,10 @@ def init_db():
     conn = get_db()
     try:
         conn.executescript(SCHEMA)
-        conn.commit()
-
-        admin = conn.execute(
-            "SELECT id FROM users WHERE username = ?", ("admin",)
-        ).fetchone()
-        if admin is None:
         conn.execute(
             """
-                INSERT INTO users (username, password_hash, display_name, is_admin, is_active, created_at)
+            INSERT OR IGNORE INTO users
+              (username, password_hash, display_name, is_admin, is_active, created_at)
             VALUES (?, ?, ?, 1, 1, ?)
             """,
             (