add global state

backend/src/state.py

@@ -0,0 +1,13 @@
+from dataclasses import dataclass
+from sqlite3 import Cursor
+
+from flask import Flask
+
+from .room import Room
+
+
+@dataclass
+class State:
+    app: Flask
+    db: Cursor
+    rooms: dict[int, Room] = {}  # { room_id: room, ... }