Re-implements envelope detection on top of the rewritten Morse decoder.
Addresses PR #160 review feedback:
- Rebase: rebuilt on current upstream/main (lifecycle state machine)
- Gap thresholds: 2.0/5.0 for envelope only; goertzel keeps 2.6/6.0
- Frequency validation: max_mhz=1766 for envelope, 30 for goertzel
- Tests: EnvelopeDetector unit tests + envelope-mode decoder test
- Envelope uses direct magnitude threshold (no SNR/noise ref)
- Goertzel path completely unchanged
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Enable direct sampling (-D 2) for RTL-SDR at HF frequencies below 24 MHz
so rtl_fm can actually receive CW signals. Add startup health check to
detect immediate rtl_fm failures. Push stopped status event from decoder
thread on EOF so the frontend auto-resets. Add frequency placeholder and
help text. Fix stop button silently swallowing errors.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Fix "What's New" section shifting up/down on smaller screens (#157) by
isolating the logo pulse animation to its own compositing layer, stabilizing
the scrollbar gutter, and pinning the welcome container dimensions.
Morse mode improvements: relocate scope and decoded output panels to the
main content area, use shared SDR device controls, and reduce panel heights
for better layout.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Use run-btn/stop-btn classes and bottom placement instead of
btn-primary/btn-danger in a flex section, and preset-btn class
for band presets. Aligns with all other mode panels.
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>
