refactor(automation): move automation logic to internal/core layer (#14)

[D3vanshC]

What this PR does

Moves automation detection, backup, and restore logic into the new internal/core/automation layer to better align with the project’s layered architecture and clearly separate responsibilities.

Changes

• Created new package internal/core/automation
• Moved automation detection logic:
  • automation/detect.go → internal/core/automation/scanner.go
  • Updated implementation to build and use domain.AutomationData
• Moved automation backup logic:
  • automation/backup.go → internal/core/automation/backup.go
  • Kept the BackupAutomation(data, *tar.Writer) signature unchanged, preserving its strategy-style interface
• Refactored restore-related logic:
  • Extracted GenerateRestorationCommands into internal/core/automation/restore.go
  • Clearly separated backup logic from restore logic
• Updated package names and imports to reflect the new core structure

Closes #14