feat: add on-disk media integrity checks and auto-remediation - #4

Node.js 20 is deprecated. The following actions target Node.js 20 but are being forced to run on Node.js 24: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5, gitleaks/gitleaks-action@ff98106e4c7b2bc287b24eaf42907196329070c7. For more information see: https://github.blog/changelog/2025-09-19-deprecation-of-node-20-on-github-actions-runners/