fix: polish gui labels and popover layout

web/app.js

@@ -224,8 +224,12 @@ function renderSignalPopover(rect, signal) {
     return `<div class="signal-popover__row"><span>${label}</span><span class="signal-popover__bar"><span class="signal-popover__fill" style="width:${width}%"></span></span><span>${Number(value).toFixed(2)}</span></div>`;
   }).join('');
   signalPopover.innerHTML = `<div class="signal-popover__title">${signal.class?.mod_type || 'Signal'}</div><div class="signal-popover__meta">${fmtMHz(signal.center_hz, 5)} · ${fmtKHz(signal.bw_hz || 0)} · ${(signal.snr_db || 0).toFixed(1)} dB SNR</div><div class="signal-popover__scores">${rows || '<div class="signal-popover__meta">No classifier scores</div>'}</div>`;
-  signalPopover.style.left = `${Math.max(8, rect.x + rect.w + 8)}px`;
-  signalPopover.style.top = `${Math.max(8, rect.y + 8)}px`;
+  const popW = 220;
+  const left = rect.x + rect.w + 8;
+  const top = rect.y + 8;
+  const maxLeft = Math.max(8, spectrumCanvas.width - popW - 8);
+  signalPopover.style.left = `${Math.max(8, Math.min(maxLeft, left))}px`;
+  signalPopover.style.top = `${Math.max(8, top)}px`;
   signalPopover.classList.add('open');
   signalPopover.setAttribute('aria-hidden', 'false');
 }
@@ -1650,3 +1654,4 @@ setInterval(fetchRecordings, 5000);
 setInterval(loadSignals, 1500);
 setInterval(loadDecoders, 10000);
 
+

web/index.html

@@ -83,10 +83,10 @@
           <div class="viz-card">
             <div class="viz-head">
               <span class="viz-label">Spectrum</span>
-              <span class="viz-hint" id="spectrumMeta">Wheel = zoom · Drag = pan · Dbl-click = reset</span>
+              <span class="viz-hint" id="spectrumMeta">Wheel = zoom · Drag = pan · Double-click = reset</span>
               <span class="viz-legend" id="cfarLegend">
                 <span class="legend-swatch"></span>
-                CFAR edge (static threshold)
+                Adaptive CFAR threshold
               </span>
             </div>
             <canvas id="spectrum"></canvas>

web/style.css

@@ -214,7 +214,7 @@ button, input, select { font: inherit; }
 
 canvas { display: block; width: 100%; height: 100%; border-radius: var(--r-sm); background: #030508; }
 .signal-popover {
-  position: absolute; z-index: 8; pointer-events: none; min-width: 180px;
+  position: absolute; z-index: 8; pointer-events: none; min-width: 180px; max-width: 220px;
   padding: 10px 12px; border-radius: 10px; border: 1px solid var(--line-hi);
   background: rgba(6, 10, 18, 0.94); box-shadow: 0 18px 50px rgba(0,0,0,0.38);
   font-size: 0.72rem; color: var(--text); display: none;