Allow SQLite DB connections across threads

Add SQLite-specific `connect_args` when creating the SQLAlchemy engine so `check_same_thread` is disabled for local SQLite usage while preserving existing settings for other databases.

api/middleware/dependencies.py

@@ -13,10 +13,15 @@ if not DATABASE_URL:
         "Please set it in your .env file or environment."
     )
 
-engine = create_engine(DATABASE_URL, pool_pre_ping=True)
+connect_args = {}
+if DATABASE_URL.startswith("sqlite"):
+    connect_args["check_same_thread"] = False
+
+engine = create_engine(DATABASE_URL, pool_pre_ping=True, connect_args=connect_args)
 SessionLocal = sessionmaker(autocommit=False, autoflush=False, bind=engine)
 
 
+
 def get_db():
     db = SessionLocal()
     try: