[fix](trx-client): default spectrum guard ratio to 0.92

Co-authored-by: OpenAI Codex <codex@openai.com>
Signed-off-by: Stan Grams <sjg@haxx.space>

src/trx-client/trx-frontend/src/lib.rs

@@ -214,7 +214,7 @@ impl FrontendRuntimeContext {
             http_show_sdr_gain_control: true,
             http_initial_map_zoom: 10,
             http_spectrum_coverage_margin_hz: 50_000,
-            http_spectrum_usable_span_ratio: 1.0,
+            http_spectrum_usable_span_ratio: 0.92,
             remote_active_rig_id: Arc::new(Mutex::new(None)),
             remote_rigs: Arc::new(Mutex::new(Vec::new())),
             owner_callsign: None,

src/trx-client/trx-frontend/trx-frontend-http/assets/web/app.js

@@ -1167,7 +1167,7 @@ function effectiveSpectrumCoverageSpanHz(sampleRateHz) {
   const sampleRate = Number(sampleRateHz);
   if (!Number.isFinite(sampleRate) || sampleRate <= 0) return 0;
   // Keep a guard band at the spectrum edges; practical usable span is slightly smaller.
-  const ratio = Number.isFinite(spectrumUsableSpanRatio) ? spectrumUsableSpanRatio : 1.0;
+  const ratio = Number.isFinite(spectrumUsableSpanRatio) ? spectrumUsableSpanRatio : 0.92;
   return sampleRate * Math.max(0.01, Math.min(1.0, ratio));
 }
 
@@ -1652,7 +1652,7 @@ let serverLat = null;
 let serverLon = null;
 let initialMapZoom = 10;
 let spectrumCoverageMarginHz = 50_000;
-let spectrumUsableSpanRatio = 1.0;
+let spectrumUsableSpanRatio = 0.92;
 
 function updateFooterBuildInfo() {
   const serverEl = document.getElementById("footer-server-build");