Add InfraScan security audit to CI/CD

[igor-soldev]

I ran a manual web scan of this repository using InfraScan, and the results showed a lot of room for improvement: https://infrascan.soldevelo.com/?scan_id=4a2acb9c-caf8-42f9-8a93-b732bf1705a1

To help manage this, I’m adding an automated security audit to the pipeline.

It’s an open-source infrastructure auditor that scans Docker images, IaC, and cloud setups for security vulnerabilities and cost optimizations.
Changes in this PR:

Workflow: Added .github/workflows/infrascan.yml. It runs a comprehensive scan on every push to master and on all Pull Requests.

Reports: Results are uploaded as artifacts, and a summary link is automatically posted as a PR comment.

Visibility: Added a "Verified by InfraScan" badge to the README.

Integrating this now will help us track and patch these vulnerabilities (most already have fixes available) and ensure no new security risks are introduced.