Initial release of simpleT — a lightweight terminal timer and stopwatch.

Features:

• Countdown timer (simplet 5m, simplet 30s, simplet 2h)
• Custom message on completion (simplet 5m "Tea is ready")
• Interactive stopwatch with real-time display (simplet)
• Background stopwatch (simplet start / simplet stop)
• Sound alert and desktop notification
• Zero dependencies: statically linked, works on any Linux