Fix: Update summarization prompt to prevent returning original text

Goal of the Changes: The primary goal of this merge request is to enhance the summarization feature in CKEditor by updating the prompt used for generating summaries. This change aims to ensure that the output effectively condenses the main ideas of the input text while explicitly excluding the original content from being repeated.

The prompt now explicitly instructs the summarization function to avoid returning the original text or restating it word-for-word. This should lead to more useful and concise summaries.