LevelResource gains a stable Id and swaps the string ScenePath for an
editor-tracked PackedScene. The old path field was never read and had
rotted - forest_1 pointed at level_forest_5.tscn, which doesn't exist,
and borrowed LEVEL_5_NAME so it would have displayed "VILLAGE - 5".
LevelCatalogue lists levels in campaign order and produces the domain's
Campaign; an authoring mistake fails at boot because Campaign.Of rejects
blank and duplicate ids. Not a domain port - nothing in the domain
resolves a level to a scene.
All 8 scenes now have a resource; campaign keeps the existing 6
(tutorial_1, village_1..5). village_6 and forest_1 are catalogued but
deliberately out of the campaign.
GameManager.LevelScenes stays until slice 10 rewrites GameManager.
