Summary

This PR optimizes the application's CPU usage by preventing unnecessary terminal redraws. Previously, the UI was being redrawn on every Render event (~60 FPS) even if the state hadn't changed, leading to high CPU load in idle states.

Key Changes:

• Conditional Redrawing: Added a needs_redraw flag to the App state. The terminal now only draws when this flag is set.
• State Change Tracking: The flag is triggered by specific events that affect the UI:
  • Tick events (time updates).
  • User input (key presses).
  • Terminal resize events.
  • Internal app events (e.g., clock completion).
• LocalTime Optimization: Updated LocalTimeState to filter out Tick events from its update stream, as time updates are already handled globally.

Test plan

1. Idle Load: Run the app with a paused timer. CPU usage should be near 0% or significantly lower than before.
2. Active Load: Start a timer. The UI should update every 100ms (on Tick) with minimal CPU impact.
3. Responsiveness: Navigate through menus and switch modes. The UI should remain snappy and responsive to all inputs.
4. Resizing: Resize the terminal window and verify the UI adapts correctly.