chore(ci): add fmt check, cargo-audit, and init_logging timing test

[EdouardZemb]

Summary

• Add cargo fmt --check and rustfmt component to CI pipeline
• Add cargo audit dependency vulnerability scanning to CI pipeline
• Add init_logging timing assertion test (< 100ms, NFR8 budget)
• Apply cargo fmt to fix pre-existing formatting across tf-config, tf-security, tf-logging

Testing

• 418 workspace tests pass, 0 failures
• cargo fmt --all -- --check clean
• cargo clippy --workspace -- -D warnings clean
• cargo audit returns 0 vulnerabilities

Checklist

• Code follows project style guidelines
• Tests pass locally
• No breaking changes