write me a smibple blender script that creates 2 buttons: one remembers (stores) the object's dimensions and other applies that stored values to the selected object

Here is a simple Blender script that creates two buttons, one to remember the dimensions of the selected object and the other to apply the stored dimensions to the selected object:

import bpy

class DimensionToolsPanel(bpy.types.Panel):
    """Creates a panel with two buttons to remember and apply object dimensions"""
    bl_label = "Dimension Tools"
    bl_idname = "OBJECT_PT_dimension_tools"
    bl_space_type = 'PROPERTIES'
    bl_region_type = 'WINDOW'
    bl_context = "object"

    def draw(self, context):
        layout = self.layout
        obj = context.active_object
        
        row = layout.row()
        row.label(text="Selected Object: " + obj.name)
        
        row = layout.row()
        row.operator("object.remember_dimensions", text="Remember Dimensions", icon='FILE_TICK')
        
        row = layout.row()
        row.operator("object.apply_remembered_dimensions", text="Apply Remembered Dimensions", icon='FILE_REFRESH')
        
class RememberDimensionsOperator(bpy.types.Operator):
    """Stores the object's dimensions"""
    bl_idname = "object.remember_dimensions"
    bl_label = "Remember Object's Dimensions"

    def execute(self, context):
        obj = context.active_object
        obj.remember_dimensions = obj.dimensions.copy()
        self.report({'INFO'}, "Remembered dimensions for object: " + obj.name)
        return {'FINISHED'}
    
class ApplyRememberedDimensionsOperator(bpy.types.Operator):
    """Applies the remembered dimensions to the object"""
    bl_idname = "object.apply_remembered_dimensions"
    bl_label = "Apply Remembered Dimensions"

    def execute(self, context):
        obj = context.active_object
        if hasattr(obj, 'remember_dimensions'):
            obj.dimensions = obj.remember_dimensions
            self.report({'INFO'}, "Applied remembered dimensions to object: " + obj.name)
        else:
            self.report({'WARNING'}, "No remembered dimensions found for object: " + obj.name)
        return {'FINISHED'}

def register():
    bpy.utils.register_class(DimensionToolsPanel)
    bpy.utils.register_class(RememberDimensionsOperator)
    bpy.utils.register_class(ApplyRememberedDimensionsOperator)

def unregister():
    bpy.utils.unregister_class(DimensionToolsPanel)
    bpy.utils.unregister_class(RememberDimensionsOperator)
    bpy.utils.unregister_class(ApplyRememberedDimensionsOperator)

if __name__ == "__main__":
    register()

You can put this script in the scripts/addons/ directory, then you can use the script by activating it via the Blender preferences.

This script creates a new panel in the Properties window called "Dimension Tools" that contains two buttons: "Remember Dimensions" and "Apply Remembered Dimensions".