Add visual harmonization tests for editor UI components and ground finish chooser

- Implemented `test_editor_visual_harmonization.gd` to validate the Stickman editor and prop editor UI layouts, ensuring proper functionality and visual consistency.
- Created `test_editor_visual_theme.gd` to verify the loading and application of visual themes in the editor, including semantic overrides and default values.
- Introduced `test_phase19_ground_finish_chooser.gd` to test the ground finish chooser's functionality, including layout responsiveness, selection behavior, and interaction with the stage.
- Added new scripts for ground finish preview and chooser UI components to enhance the editor's visual representation of ground finishes.

scripts/editors/prop/prop_canvas.gd

@@ -121,6 +121,7 @@ var _pan_offset: Vector2 = Vector2.ZERO
 var _grid_size: int = 15
 var _snap_enabled: bool = false
 var _has_clipboard: bool = false
+var _create_point_armed: bool = false
 var _context_menu: PopupMenu
 var _edit_mode: EditMode = EditMode.TRANSFORM
 var _anchor_overlay: RefCounted
@@ -214,6 +215,8 @@ func set_edit_mode(mode: int) -> void:
 	if _stage_size_preview_active:
 		cancel_stage_size_preview()
 	_edit_mode = m
+	if _edit_mode != EditMode.POINTS:
+		_create_point_armed = false
 	if _edit_mode != EditMode.TRANSFORM:
 		set_whole_prop_resize_enabled(false)
 	_drag_mode = DragMode.NONE
@@ -225,6 +228,21 @@ func set_edit_mode(mode: int) -> void:
 func get_edit_mode() -> int:
 	return _edit_mode
 
+
+func arm_create_point() -> void:
+	set_edit_mode(EditMode.POINTS)
+	_create_point_armed = true
+	queue_redraw()
+
+
+func cancel_create_point() -> void:
+	_create_point_armed = false
+	queue_redraw()
+
+
+func is_create_point_armed() -> bool:
+	return _create_point_armed
+
 func set_anchor_data(data: Variant) -> void:
 	if _anchor_overlay == null: _anchor_overlay = PropAnchorOverlayScript.new()
 	_anchor_overlay.set_anchor_data(data)
@@ -1254,7 +1272,10 @@ func _on_canvas_gui_input(event: InputEvent) -> void:
 			return
 		if mb.button_index == MOUSE_BUTTON_LEFT:
 			if mb.pressed:
-				_handle_left_press(world_pos)
+				if _create_point_armed and _edit_mode == EditMode.POINTS:
+					_create_point_from_toolbar(world_pos)
+				else:
+					_handle_left_press(world_pos)
 			else:
 				_handle_left_release()
 
@@ -1464,6 +1485,21 @@ func _handle_left_press(world_pos: Vector2) -> void:
 	shape_selected.emit(-1)
 
 
+func _create_point_from_toolbar(world_pos: Vector2) -> void:
+	var shape_idx: int = hit_test_segment(world_pos)
+	if shape_idx < 0:
+		return
+	_selected_shape_idx = shape_idx
+	shape_selected.emit(shape_idx)
+	var new_vertex_index: int = create_point_on_edge(world_pos)
+	if new_vertex_index < 0:
+		return
+	_create_point_armed = false
+	_drag_mode = DragMode.NONE
+	_emit_changed()
+	queue_redraw()
+
+
 func _handle_drag_motion(mm: InputEventMouseMotion, world_pos: Vector2, ctrl_pressed: bool) -> void:
 	match _drag_mode:
 		DragMode.VERTEX: