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>

scenes/levels/warcraft/WarCraft.tscn

@@ -49,7 +49,7 @@ background_energy_multiplier = 0.6
 sky = SubResource("1")
 ambient_light_color = Color(0.694118, 0.168627, 0.67451, 1)
 ambient_light_sky_contribution = 0.5
-ambient_light_energy = 0.4
+ambient_light_energy = 1.0
 tonemap_mode = 2
 ssr_enabled = true
 glow_enabled = true

scenes/levels/warcraft/env_warcraft.tres

@@ -11,7 +11,7 @@ sky = SubResource( 2 )
 background_color = Color( 0.188235, 0.133333, 0.133333, 1 )
 background_energy_multiplier = 0.6
 ambient_light_color = Color( 0.694118, 0.168627, 0.67451, 1 )
-ambient_light_energy = 0.4
+ambient_light_energy = 1.0
 ambient_light_sky_contribution = 0.5
 fog_enabled = true
 fog_mode = 1