[Enhancement] Implement Tab Completion

[aphexlog]

Allow users to press Tab to complete commands and paths.

Tasks:

• Detect Tab key press.
• Suggest available commands or paths.
• Implement fuzzy matching.

Acceptance Criteria:

• Pressing Tab on ls suggests available files.
• Pressing Tab on git suggests Git subcommands.
• Pressing Tab on cd D auto-completes cd Documents.