✨(backend) introduce a creation callback endpoint

Necessary in cross browser context situation, where we need to
pass data of a room newly created between two different windows.

This happens in Calendar integration.

src/backend/core/services/room_creation.py

@@ -0,0 +1,37 @@
+"""Room creation service."""
+
+from django.conf import settings
+from django.core.cache import cache
+
+
+class RoomCreation:
+    """Room creation related methods"""
+
+    @staticmethod
+    def _get_cache_key(callback_id):
+        """Generate a standardized cache key for room creation callbacks."""
+        return f"room-creation-callback_{callback_id}"
+
+    def persist_callback_state(self, callback_id: str, room) -> None:
+        """Store room data in cache using the callback ID as an identifier."""
+        data = {
+            "slug": room.slug,
+        }
+        cache.set(
+            self._get_cache_key(callback_id),
+            data,
+            timeout=settings.ROOM_CREATION_CALLBACK_CACHE_TIMEOUT,
+        )
+
+    def get_callback_state(self, callback_id: str) -> dict:
+        """Retrieve and clear cached room data for the given callback ID."""
+
+        cache_key = self._get_cache_key(callback_id)
+        data = cache.get(cache_key)
+
+        if not data:
+            return {}
+
+        cache.delete(cache_key)
+
+        return data