Chrome extension to manipulate google doc - proof of concept

We need a chrome extension that will inject a react.js section into a google document page (See included graphic). The extension should sit at the bottom of the document and not interfere with scrolling or viewing the document. The extension's major function is to add an underline color to one sentence at a time AND display that sentence within the control. On startup, the first sentence should be displayed in the control and the sentence in the document should be underlined. There are two navigation buttons that should move to the next or previous sentence. Sentence ends are period, question mark and exclamation. (.?!). See graphic mock-up as an example. The underline should not interfere with error warnings (red underlines) from other apps. The screenshot shows the first sentence underlined. It also shows one sentence underlined that has spelling errors. Notice that both can be seen. The color area should be a simple color selector or make a suggestion on how to pick a color. The goal is a proof of concept to help with reviewing text for a group of people. This needs to be a functional app, not finished. The goal is to show proof of concept. You should have expert skills with chrome extensions. To show that you can follow instructions and that you read this fully, put your favorite animal name as the first word of your bid.