What

Add a practice mode to the CWX panel that plays sidetone locally without keying the transmitter. This lets operators practice sending CW without going on air.

Why

New CW operators need a way to practice timing and character formation without transmitting. SmartSDR includes this as part of its CW keyer.

Suggested Behavior

• Toggle button (e.g. "Practice") in the CWX panel bottom bar or setup view
• When enabled, keyboard input plays sidetone through the local audio engine at the configured CW pitch and speed
• No cwx send commands are sent to the radio — purely client-side
• WPM speed control still works in practice mode
• Visual feedback (sent character highlighting) still works

Protocol

No radio commands needed — this is entirely client-side audio generation.