OpenPulseHF v0.2.1

Headline: CE-SSB transmit envelope conditioning — controlled-envelope SSB (Hershberger W9GR, QEX 2014) applied as an adaptive, per-mode, default-on TX conditioner for the high-PAPR multicarrier modes (OFDM / SC-FDMA). Believed to be the first open-source HF data modem to do this.

Added

• CE-SSB (openpulse_dsp::cessb): look-ahead peak-stretcher that raises average TX power at fixed PEP. Per-mode gate (ModemEngine::cessb_benefits → OFDM*/SCFDMA*), [modem] cessb_enabled config, SetCessb control command, openpulse daemon set-cessb CLI, and a panel "CE-SSB" toggle.
  • Channel-sim: +1.6 / +2.7 / +3.8 dB average power on OFDM52 (2.5/2.0/1.5×rms) at zero BER cost.
  • On-air confirmed: +1.18 dB (FT-991A, 2 m).
  • Software ACPR + on-air SDR spectral-mask checks: no added splatter on QPSK OFDM; on dense OFDM-HOM the larger average-power boost only splatters if the PA's ALC is over-driven (set audio drive for moderate ALC).
• Measurement tests: cessb_benefits_hold_on_ofdm_hom, cessb_acpr_spectral_regrowth.
• Operator panel: Messages presented as a tab alongside the Event Log.

Full history in CHANGELOG.md.