Run godot --convert-3to4 (automated conversion)

Apply Godot 4.6 automated conversion: renames Spatial.translate->position,
margin_*->offset_*, tool->@tool, .empty()->.is_empty(), DynamicFont->FontFile,
onready->@onready, export()->@export, and many more.

127 files changed by the tool. Manual fixes still required for:
 - godot_db_manager plugin (incompatible APIs: WindowDialog, Tabs, etc.)
 - lod plugin (Spatial -> Node3D renames)
 - ResourceLoader.load_interactive removed -> load_threaded_request
 - OS.set_window_fullscreen removed -> DisplayServer
 - Viewport.set_size_override removed

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

addons/godot_db_manager/dlgs/error_dlg.tscn

@@ -1,11 +1,11 @@
-[gd_scene format=2]
-
-[node name="error_dlg" type="AcceptDialog"]
-visible = true
-anchor_right = 0.139
-anchor_bottom = 0.099
-margin_right = 0.599976
-margin_bottom = -0.100006
-popup_exclusive = true
-window_title = "Error"
-dialog_autowrap = true
+[gd_scene format=2]
+
+[node name="error_dlg" type="AcceptDialog"]
+visible = true
+anchor_right = 0.139
+anchor_bottom = 0.099
+offset_right = 0.599976
+offset_bottom = -0.100006
+exclusive = true
+window_title = "Error"
+dialog_autowrap = true