Fix gdlint findings in Global / Database / Levels

- Global.gd: move @onready var animation below the regular vars
  (gdlint class-definitions-order expects onready vars after
  public/private vars).
- Database.gd::DB: move the three _*_PROPS constants above the vars
  (constants come before vars in a class body).
- Levels.gd:_search_button_to_use: drop the elif after a branch
  that returns (no-elif-return).
- Levels.gd:_gyroscope_changed_{down,up}: continuation lines of the
  multi-line return mixed two tabs + three spaces; normalised to
  pure tabs.

No semantic change: @onready is property-level so source ordering
doesn't affect init; elif after a return is equivalent to if; the
continuation indent is cosmetic.

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

scripts/Global.gd

@@ -2,8 +2,6 @@ extends Control
 
 # Application root: async scene loading + reference to the loaded Database.
 
-@onready var animation: AnimationPlayer = Loading.get_node("AnimLoading")
-
 var current_scene: Node = null
 var current_scene_int: int = -1
 var wait_frames: int = 1
@@ -11,6 +9,8 @@ var database: RefCounted = null
 var loaded: bool = false
 var _loading_path: String = ""
 
+@onready var animation: AnimationPlayer = Loading.get_node("AnimLoading")
+
 func _ready() -> void:
 	database = load("res://scripts/Database.gd").new().initialize()
 	_initialize_current_scene()