fix(ci): bump rust-ci-reusable SHA past standards#334 fix

standards#334 (merged 2026-06-01) wrapped the bare job-level `if:` in
rust-ci-reusable.yml that GH Actions was silently rejecting since
2026-05-26, producing the 0s-duration "completed failure" runs tracked
in standards#322. Bumping panic-attack's pin to d7c3b8f7 (current
standards/main HEAD; includes #334 and the follow-up canonical-wrapper
SHA sweep #335) so rust-ci.yml stops being baseline-red.

Refs: hyperpolymath/standards#322, hyperpolymath/standards#334.

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

Author: hyperpolymath

.github/workflows/rust-ci.yml

@@ -14,4 +14,4 @@ permissions:
 
 jobs:
   rust-ci:
-    uses: hyperpolymath/standards/.github/workflows/rust-ci-reusable.yml@cc5a372af1af1b202c17f1b21efd954e6c038bef
+    uses: hyperpolymath/standards/.github/workflows/rust-ci-reusable.yml@d7c3b8f75d70ab640e6f37a4c8f9e6e8f2b6df56