fix: improve metadata frame detection and update version to v0.12.1

sfm/sfm_webapp.html

@@ -1574,7 +1574,10 @@ function _buildWaveformCharts(data, chartsEl, emptyEl, chartsStore) {
     return;
   }
 
-  const times = Array.from({length: decoded}, (_, i) => ((i - pretrig) / sr * 1000).toFixed(2));
+  // Clip to configured record window — device streams extra zero-padded frames
+  // beyond total_samples; showing them just adds a flat tail to every chart.
+  const display = data.total_samples ? Math.min(data.total_samples, decoded) : decoded;
+  const times = Array.from({length: display}, (_, i) => ((i - pretrig) / sr * 1000).toFixed(2));
   if (emptyEl) emptyEl.style.display = 'none';
   chartsEl.style.display = 'flex';
   chartsEl.style.flexDirection = 'column';
@@ -1592,7 +1595,7 @@ function _buildWaveformCharts(data, chartsEl, emptyEl, chartsStore) {
 
     if (isGeo) {
       const scale = geoRange / 32767;
-      plotData  = samples.map(s => s * scale);
+      plotData  = samples.slice(0, display).map(s => s * scale);
       // Use the device-recorded peak from the 0C waveform record — authoritative
       // and matches Blastware. Computing from raw samples can catch rogue
       // near-full-scale values from decoding artifacts.
@@ -1603,9 +1606,10 @@ function _buildWaveformCharts(data, chartsEl, emptyEl, chartsStore) {
       ttFmt     = v => `${ch}: ${v.toFixed(5)} in/s`;
       tickFmt   = v => v.toFixed(4);
     } else {
-      const peakCounts = Math.max(...samples.map(Math.abs));
+      const clippedMic = samples.slice(0, display);
+      const peakCounts = Math.max(...clippedMic.map(Math.abs));
       const micScale   = (micPeakPsi !== null && peakCounts > 0) ? Math.abs(micPeakPsi) / peakCounts : 1.0;
-      plotData  = samples.map(s => s * micScale);
+      plotData  = clippedMic.map(s => s * micScale);
       const peakPsi = Math.max(...plotData.map(Math.abs));
       const peakDbl = peakPsi > 0 ? 20 * Math.log10(peakPsi / DBL_REF) : -Infinity;
       peakLabel = `${peakDbl.toFixed(1)} dBL`;