Fix Levels.gd type inference + Database integer-division warning + brighten scenes

- scenes/levels/Levels.gd: replace 'var level := Global.database
  .level_by_index(...)' with explicit 'var level: LevelEntry = ...'.
  Global.database is typed RefCounted so the parser can't see DB's
  return types through the walrus operator. Two callsites.
- scripts/Database.gd: annotate the two 'range(data.size() / W)'
  loops with @warning_ignore('integer_division'). The division is
  intentional (row count = bytes / row width); Godot 4 warns by
  default in case the slash was a typo.
- env: ambient_light_energy 0.4 -> 1.0 in WarCraft.tscn, Home.tscn
  and env_warcraft.tres. 0.4 left the floor pitch-black; 1.0 is a
  compromise between the original 1.55 (oversaturated) and this.
  Re-baking the lightmap in the editor is still the right fix —
  this commit just keeps the scene playable in the meantime.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

scripts/Database.gd

@@ -67,6 +67,7 @@ class DB extends RefCounted:
 	func _load_levels(data: Array) -> Array[LevelEntry]:
 		var result: Array[LevelEntry] = []
 		const W := 2
+		@warning_ignore("integer_division")
 		for i in range(data.size() / W):
 			var l := LevelEntry.new()
 			l.index = i
@@ -78,6 +79,7 @@ class DB extends RefCounted:
 	func _load_scenes(data: Array) -> Array[SceneEntry]:
 		var result: Array[SceneEntry] = []
 		const W := 7
+		@warning_ignore("integer_division")
 		for i in range(data.size() / W):
 			var s := SceneEntry.new()
 			s.lock = bool(int(data[i * W + 0]))