ci: repin orphan reusable SHAs (97df7621/4fdf4314 → live SHAs)

The caller workflow(s) pinned hyperpolymath/standards reusable workflow(s)
at orphan SHAs no longer reachable from `standards/main`. Read-only
Contents API resolves the blob (cached), so code-review tooling does
not catch this; `workflow_call` at run-time refuses orphan SHAs and
emits "workflow file issue" with zero jobs created.

Replacements:
  hypatia-scan-reusable.yml: @97df7621... → @915139d73560e65a8240b8fc7768698658502c89
  rust-ci-reusable.yml:      @4fdf4314... → @cc5a372af1af1b202c17f1b21efd954e6c038bef

Audit:   hyperpolymath/standards/docs/audits/audit-hypatia-pin-orphan-2026-05-27.adoc
Detector: hypatia rule WF016 (hyperpolymath/hypatia#393)

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: hyperpolymath

.github/workflows/hypatia-scan.yml

@@ -25,5 +25,5 @@ permissions:
 
 jobs:
   hypatia:
-    uses: hyperpolymath/standards/.github/workflows/hypatia-scan-reusable.yml@97df762107501909f50bb770e9bc200b6c415600
+    uses: hyperpolymath/standards/.github/workflows/hypatia-scan-reusable.yml@915139d73560e65a8240b8fc7768698658502c89
     secrets: inherit