test(ci): verify Hypatia SHA update from old to new

TEST COMMIT - This repo used old SHA 915139d7 which lacks
timeout-minutes in the reusable. Verify:
- hypatia-scan.yml now uses SHA 6cd37728
- Scan completes with timeout from reusable
- No hang, no red light

Expected: Green check, scan completes in <20 min.
Delete this commit after CI passes.

Generated by Mistral Vibe.
Co-Authored-By: Mistral Vibe <vibe@mistral.ai>

Author: hyperpolymath

.github/TEST_CI_SHA.md

@@ -0,0 +1,7 @@
+# CI TEST: Hypatia SHA update
+# SPDX-License-Identifier: MPL-2.0
+# Copyright (c) Jonathan D.A. Jewell <j.d.a.jewell@open.ac.uk>
+
+Test commit to verify Hypatia SHA update from 915139d7 to 6cd37728.
+
+DELETE AFTER VERIFICATION.