feat: split scene node modifiers into recursive and non-recursive variants

[sebcrozet]

SceneNode3d and SceneNode2d: Recursive vs Non-Recursive Methods

Methods that previously modified both a node and all its descendants now only modify the current node.
Use the new _recursive suffix variants for the previous behavior.

Renamed methods (now non-recursive by default):

SceneNode3d:

• set_material, set_material_with_name
• set_color, set_texture, set_texture_from_file, set_texture_from_memory, set_texture_with_name
• set_lines_width, set_lines_color, set_points_size, set_points_color
• set_surface_rendering_activation, enable_backface_culling
• set_local_scale, set_visible
• set_metallic, set_roughness, set_emissive
• set_normal_map, set_normal_map_from_file, set_normal_map_from_memory, set_normal_map_with_name
• set_ao_map, set_ao_map_from_file, set_ao_map_from_memory, set_ao_map_with_name
• set_emissive_map, set_emissive_map_from_file, set_emissive_map_from_memory, set_emissive_map_with_name
• modify_vertices, read_vertices, recompute_normals, modify_normals, read_normals
• modify_uvs, read_uvs, modify_faces, read_faces

SceneNode2d:

• set_material, set_material_with_name
• set_color, set_texture, set_texture_from_file, set_texture_from_memory, set_texture_with_name
• set_lines_width, set_lines_color, set_points_size, set_points_color
• set_surface_rendering_activation
• set_local_scale, set_visible
• modify_vertices, read_vertices, modify_uvs, read_uvs, modify_faces, read_faces

New recursive variants:
All the above methods now have _recursive suffix versions (e.g., set_color_recursive) that apply to the node and all descendants.

Helper method renames:

• apply_to_objects_mut → apply_to_objects_mut_recursive / apply_to_object_mut (new)
• apply_to_objects → apply_to_objects_recursive / apply_to_object (new)
• apply_to_scene_nodes_mut → apply_to_scene_nodes_mut_recursive
• apply_to_scene_nodes → apply_to_scene_nodes_recursive