TruthByte v0.2.1

feat: implement disk scanning and refactor frontend architecture

This commit introduces a major UX overhaul by replacing the file picker with a native-like disk selection dashboard and refactors the frontend to separate IO logic from UI components.

Changes:
- frontend: Create `useDiagnosisController` hook to separate Tauri IO and business logic from views.
- frontend: Redesign `SetupView` to display a grid of available system disks with usage visualization.
- frontend: Add `disks` and `isScanningDisks` state to Zustand store.
- backend: Add `sysinfo` dependency and implement `get_system_disks` command to list system drives.
- backend: Expose disk information (mount point, available space, removable status) to the frontend.
- ui: Enhance visual experience with entry animations, glassmorphism effects, and interactive disk cards.