Add `Dry-Run / Preview` mode (CLI + TUI)

[pashkov256]

Goal

Allow users to preview what would be deleted/trashed without actually modifying the filesystem.

Why (sanity check)

• Not nonsense: for deletion tools this is one of the highest-trust features.
• Low risk, big UX win, helps debugging and safer automation.

CLI activation

• Add flag: --dry-run
• Example:

deletor -cli -d ~/Downloads -e mp4,zip --min-size 10mb --dry-run
deletor -cli -d . --rules --dry-run