fix(ci): bump rust-ci-reusable SHA past standards#334 fix (recover rust-ci.yml from baseline-red) (#97)

## Summary

\`standards#334\` (merged 2026-06-01T18:37Z) wrapped the bare job-level
\`if:\` in \`rust-ci-reusable.yml\` that GH Actions had been silently
rejecting since 2026-05-26 — the parse failure tracked in standards#322
that produced 0s-duration "completed failure" runs across the estate.

Bumps panic-attack's pin from \`cc5a372a\` (pre-fix) to \`d7c3b8f7\`
(current standards/main HEAD; includes #334 and follow-up
canonical-wrapper SHA sweep #335).

## Test plan

- [x] SHA exists on standards/main: \`gh api
/repos/hyperpolymath/standards/commits/d7c3b8f75d70ab640e6f37a4c8f9e6e8f2b6df56\`
returns 200
- [x] Includes standards#334 fix in its history
- [ ] On merge: rust-ci.yml run should report \`name='Rust CI'\`
(parsed) instead of \`name='.github/workflows/rust-ci.yml'\` (path
fallback)
- [ ] Jobs (\`check\` + \`test\`) should actually execute rather than
0s-fail

## Refs

- Closes panic-attack#84 retroactively (orphan-SHA hypothesis was
incorrect; real bug fixed at source).
- Refs hyperpolymath/standards#322, hyperpolymath/standards#334.

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

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