Refactor auth for better readability

**Description**
Currently validation lacks proper backup support.

**Proposed solution**
Add configurable backup with sensible defaults.

**Priority**: Low/Medium

Start by locating the authentication and validation entry points in the Shell project and reading how validation currently handles missing or failed backup support. Define the configuration surface and sensible defaults from the existing behavior, then verify that configurable backup is covered by the relevant checks or tests.

Written by the indexing model from the issue text.