Restore strict Clippy on Rust 1.97

[juangaitanv]

Summary

Restore the strict all-target Clippy gate on Rust 1.97 by resolving its four current lint errors. The changes are behavior-preserving: avoid a test-only PathBuf clone, express a nonempty assertion directly, remove a terminal return, and move the unchanged SARIF test module after production items.

This keeps the project’s local push gate and CI-compatible strict lint command green on current stable Rust. The SARIF test module contents are unchanged; their before/after SHA-256 hashes match.

Related issue

None.

Checklist

• make ci passes locally (the same command CI runs — see CONTRIBUTING.md)
• Ran make bootstrap once so pre-commit/pre-push hooks are active
• Added/updated tests for the change
• Updated docs/rules where relevant (not applicable)

Verification

• cargo clippy --all-targets --all-features -- -D warnings — passed
• make check — 201 tests passed; all 4 checks passed
• make ci — exited 0; strict Clippy, format, audit, tests, acceptance, coverage, and architecture passed; existing complexity and CRAP findings remained advisory
• git push pre-push hook — Clippy, format, acceptance, and architecture passed

[yhoztak]

LGTM