Remove duplicate OpenSSF Scorecard workflow (scorecard-enforcer.yml) (#618)

## What

Removes the legacy `.github/workflows/scorecard-enforcer.yml`.

## Why

This repo runs the OpenSSF Scorecard scan **twice** on every push:

- `scorecard.yml` — delegates to the shared `hyperpolymath/standards`
  scorecard **reusable** workflow (the modern, canonical path), and
- `scorecard-enforcer.yml` — a legacy self-contained job that runs its
**own**
  full Scorecard scan + SARIF upload again.

The governance **Check Workflow Staleness** gate explicitly requires
this:
> Remove legacy scorecard-enforcer.yml …

Deleting the enforcer leaves a single Scorecard scan (via the reusable
workflow) and removes the redundant Actions run.

## Note (separate follow-up)

The same staleness gate also asks to refresh the Hypatia + Scorecard
reusable
**pins** to the current `hyperpolymath/standards` SHA. That needs read
access
to `hyperpolymath/standards` (not in this session's scope), so it's left
as a
follow-up — the staleness check may stay red on those pin items until
then.
This PR addresses only the duplicate-scan removal.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

https://claude.ai/code/session_0196movYBRwNw8vkLRaaFoTu

---
_Generated by [Claude
Code](https://claude.ai/code/session_0196movYBRwNw8vkLRaaFoTu)_

Co-authored-by: Claude <noreply@anthropic.com>

Author: hyperpolymath