Stabilize CI/Audit workflows by pinning toolchain action and ensuring lockfile for audit

[Copilot]

The CI/CD pipeline was failing, requiring a way to reproduce workflow parts locally and a focused fix to restore workflow reliability without changing application behavior.

• CI toolchain resolution
  • Switched Rust toolchain install steps to the stable action and explicitly set the MSRV toolchain to avoid action ref resolution failures.
• Security audit reliability
  • Ensured Cargo.lock is generated during audit runs so cargo audit can execute even though the lockfile is gitignored.

Example adjustment:

- name: Ensure Cargo.lock exists
  run: cargo generate-lockfile

Original prompt

You are the CEO. You have multiple subagents at your disposal. The buck stops with you.

The CI/ CD pipeline is failing.

• Find a way to test each of the parts of the CI / CD pipeline without actually having to run the pipeline. Create a similar script and execute. Find a way to reproduce the failures.
• Holistically go through the codebase to learn and understand the issue in depth.
• Search the internet to find out possible solutions and for knowledge
• Think through, reason hard and deep and figure out a holistic fix
• Make the changes, test it throughly, make sure that your changes would succeed when run in the CI / CD pipeline
• Run a critic in a sub agent. Think through its findings
• Run a reviewer in a sub agent. Address if you think any of its concerns are valid
• Review and cross check your work

Custom agent used: CI/CD Expert
Expert in GitHub Actions, cross-platform builds, and release automation for Rust

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