The persist-text-scale Emacs package provides persist-text-scale-mode, which
ensures that all adjustments made with text-scale-increase and
text-scale-decrease are persisted and restored across sessions. As a result,
the text size in each buffer remains consistent, even after restarting Emacs.

This package also facilitates grouping buffers into categories, allowing
buffers within the same category to share a consistent text scale. This
ensures uniform font sizes when adjusting text scaling. By default:
- Each file-visiting buffer has its own independent text scale.
- Special buffers, identified by their buffer names, each retain their own
  text scale setting.
- All Dired buffers maintain the same font size, treating Dired as a unified
  "file explorer" where the text scale remains consistent across different
  buffers.

This category-based behavior can be further customized by assigning a
function to the persist-text-scale-buffer-category-function variable. The
function determines how buffers are categorized by returning a category
identifier (string) based on the buffer's context. Buffers within the same
category will share the same text scale.