PR Description

Summary

This PR fixes the Gulp configuration so it matches the actual repository structure and does not fail immediately when contributors try to run it.

Problem

The current Gulp setup had multiple guaranteed breakpoints:

• The CommonJS gulpfile.js used an incorrect Babel preset and was not reliable to run.
• The ESM gulpfile.mjs referenced:
  - a SASS path that does not exist in this repo (scss/**/*.scss)
  - gulp-rename, which was not installed, causing an immediate runtime error

As a result, running Gulp would fail even before any build logic could execute.

Changes

• Retired the broken CommonJS gulpfile by renaming it to gulpfile.legacy.js and marking it as legacy / reference-only.

• Updated gulpfile.mjs to match the repo’s actual SASS layout:
  - scss/**/*.scss → css/**/*.sass

• Added the missing dependency required by gulpfile.mjs:
  - added gulp-rename to devDependencies

Why this change is safe

• No build system rewrite.
• No new tasks or output files added.
• No changes to existing CSS or JS output.
• This only aligns existing tooling with the files and dependencies already present in the repo.

How to test

expected -

• Gulp now loads the ESM gulpfile without crashing.

• Gulp runs successfully; Sass emits deprecation warnings for legacy @import usage, which existed before this change and are not addressed here to keep the PR focused. It’s a warning, not a failure, and nothing breaks .

Notes

• npm install reports existing vulnerabilities via npm audit.
• This PR intentionally does not address them to keep the scope limited to fixing Gulp breakpoints only.