✨(project) add CRUD API endpoints for Rooms and ResourceAccess models

Introduce CRUD API endpoints for the Rooms and ResourceAccess models.
The code follows the Magnify logic, with the exception that token generation
has been removed and replaced by a TODO item with a mocked value.

Proper integration of LiveKit will be added in future commits.

With the removal of group logic, some complex query sets can be simplified.
Previously, we checked for both direct and indirect access to a room.
Indirect access meant a room was shared with a group, and the user was a
member of that group. I haven’t simplified those query set, as I preferred
isolate changes in dedicated commits.

Additionally, all previous tests are still passing, although tests related
to groups have been removed.

src/backend/core/admin.py

@@ -62,3 +62,17 @@ class UserAdmin(auth_admin.UserAdmin):
     ordering = ("is_active", "-is_superuser", "-is_staff", "-is_device", "-updated_at")
     readonly_fields = ("id", "sub", "email", "created_at", "updated_at")
     search_fields = ("id", "sub", "admin_email", "email")
+
+
+class ResourceAccessInline(admin.TabularInline):
+    """Admin class for the room user access model"""
+
+    model = models.ResourceAccess
+    extra = 0
+
+
+@admin.register(models.Room)
+class RoomAdmin(admin.ModelAdmin):
+    """Room admin interface declaration."""
+
+    inlines = (ResourceAccessInline,)