Implement cargo audit security automation for #439

[josecelano]

Summary

Implements issue #439 by adding automated Cargo dependency security auditing, documenting the initial scan, and remediating the reported vulnerable dependency versions.

Changes

• Add a scheduled and manually runnable Cargo security audit workflow
• Add dependency security report documentation under docs/security/dependencies
• Update vulnerable dependency versions to clear current cargo-audit findings
• Add the Cargo Security Audit badge to the main README

Commit Structure

• build: [Automate Cargo Audit Security Scanning and Dependency Remediation #439] update vulnerable dependency versions
• docs: [Automate Cargo Audit Security Scanning and Dependency Remediation #439] add cargo audit security reports
• ci: [Automate Cargo Audit Security Scanning and Dependency Remediation #439] add cargo security audit workflow

Validation

• ./scripts/pre-commit.sh
• cargo audit

Closes #439

[josecelano]

ACK 1a5dc56