validate_frequency() defaults to 24-1766 MHz (VHF/UHF range), but Morse/CW
operates on HF bands (0.5-30 MHz). Pass explicit min/max to allow HF frequencies.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
New signal mode for decoding Morse code (CW) transmissions via SDR.
Includes route blueprint, utility decoder, frontend UI, and tests.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>