docs: remove the animated README footer banner

[zaccesss]

What

Removes the leftover animated capsule-render.vercel.app footer banner from the root README, along with the centered "Made with" block it lived in, which is a style no longer used anywhere else in the project's repositories. Replaces it with a plain closing line.

While in there, this also fixes two small things:

• The version badge was stuck at 1.2.2 while CHANGELOG.md was already at 1.2.3, now bumped to 1.2.4 to match this release
• A duplicated --- divider right before the old footer is gone

I checked the top of the README first, there was no matching header banner or typing-svg animation to remove, this is a footer-only fix. I also verified the course section and file counts already in the README (182 files, 12 sections) still match CHANGELOG.md and what is on disk, so no other content needed updating. 00-welcome/README.md and every numbered course-content file are untouched.

Other root docs

I read through the other root-level docs (CONTRIBUTING.md, CODE_OF_CONDUCT.md, SECURITY.md, SUPPORT.md, HALL_OF_FAME.md, ROADMAP.md, FAQ.md, CITATION.cff) looking for staleness. One clear, unambiguous fix folded in here:

• CITATION.cff still said version 1.2.2, dated 2026-08-03, bumped to 1.2.4 dated 2026-08-05 to match this release

Two things I found but deliberately left alone because they are not unambiguous:

• ROADMAP.md still headlines "Current version: v1.2.0" and its own file/section table does not sum to the "15 sections" it claims. Fixing the version stamp without catching the rest of the document up to the CHANGELOG (it stops narrating at v1.2.0) would leave it internally inconsistent. I am not sure a full ROADMAP rewrite is wanted here.
• CONTRIBUTING.md's own Writing Style Guide documents the "Made with 🔓 ... Access Granted. Success Unlocked." block as the required footer for every file in the course. It is still used consistently in HALL_OF_FAME.md, SUPPORT.md, SECURITY.md and CODE_OF_CONDUCT.md. That is a different, static, non-animated element from the capsule-render banner removed here. Removing it from those files would contradict the course's own documented style guide, so I left it as is.

I also checked .github/workflows/ against the fleet's centralized automation approach. This repo intentionally only has linkcheck.yml and markdownlint.yml, per the 1.2.2 changelog entry that retired the local automerge-dependabot.yml, update-pr-branches.yml and stale.yml workflows in favour of repo-ops' centralized handling. Nothing missing there.

Ran a local lychee check against the changed markdown files with the same flags CI uses, 0 errors.

Closes #75

[zaccesss]

Checked, CI is green now that the unrelated dead link is fixed on main. Good to merge.