Utility band buttons (WWV/GEN/2200/630) lose the tuning-range gate after a band-panel rebuild

Summary

The tuning-range gate added in #4503 (SpectrumOverlayMenu::applyTuningRangeToBandButtons()) stops covering the utility band buttons — WWV, GEN, 2200, 630 — after the band panel is rebuilt.

Detail

Buttons are gated by being registered in m_bandBtnFreqs. There are two places the utility row is built:

• Original construction (SpectrumOverlayMenu.cpp:455) — registers them:

  m_bandBtnFreqs.append({btn, freq});
  

• setXvtrBands() rebuild (SpectrumOverlayMenu.cpp:2678-2702) — the same loop, but with no m_bandBtnFreqs.append.

setXvtrBands() clears m_bandBtnFreqs at the top (:2538) because the whole panel is destroyed and rebuilt. HF bands are re-registered via makeBandBtn() and declared bands at :2621, so those stay gated — but the utility buttons are not re-registered and silently drop out of the gate.

The rebuild runs from MainWindow.cpp:5294, wired to RadioModel::infoChanged, so it happens routinely rather than rarely.

Effect on an HL2: 2200 m (0.136 MHz) and 630 m (0.475 MHz) sit below the reported tuning range and are correctly greyed out on first build, then become live again after the first rebuild.

Not a bug: the XVTR buttons

The XVTR band buttons are also absent from m_bandBtnFreqs, but that is correct and should stay that way. A transverter's rfFreqMhz is by definition a frequency the radio cannot tune natively — gating those buttons by the radio's own tuning range would disable exactly the bands the transverter exists to provide.

Suggested fix

Add the m_bandBtnFreqs.append({btn, freq}) to the utility-button branch of the setXvtrBands() rebuild, matching :455. The gate is already correctly re-applied at the end of that function (:2796), so registration is the only missing piece.

Start in SpectrumOverlayMenu.cpp at the utility-row construction around line 455 and the setXvtrBands() rebuild around lines 2538 and 2678-2702. Compare how utility and HF buttons are registered, then verify the existing gate is re-applied near line 2796. Done means WWV, GEN, 2200, and 630 remain range-gated after rebuilds while XVTR buttons remain excluded.