Feature: preview equation on hover for referenced equations.

Inspired by [LaTeX Workshop](https://marketplace.visualstudio.com/items?itemName=James-Yu.latex-workshop), the goal is to dynamically display the referenced equation when hovered over a reference link in a **notie** page. The result should look like the following:  However, instead of hovering over an equation when editing, user should hover over a rendered reference link. For example, in the following **notie** render below, <img width="1049" alt="image" src="https://github.com/user-attachments/assets/3eaad7f2-8a2f-4992-9acf-6b9f88f22932"> When users hover over `(1.11)`, **notie** should dynamically display the rendered equation `D = E + F`.