Align CMTS OFDMA PreEqualization results visual with standards and frequency-based group delay

- update visual header to include required Visual Constraints line for canonical rule traceability
- remove vendor-specific runtime fallbacks by defaulting missing system model and software values to N/A
- map group delay points to carrier frequency in MHz and switch group delay chart x-axis from Index to MHz
- align base dark palette tokens to canonical dark-blue values for consistent visual shell styling
- sync updated visualizer script into PyPNM-CMTS Results request and regenerate visual docs preview outputs - 2026-03-08 18:33:41

Author: mgarcia01752

docs/visual-previews/PyPNM-CMTS/ServingGroup/Upstream/OFDMA/PreEqualization/Results/basic.html

@@ -17,6 +17,7 @@ Preview is best-effort. Some templates may rely on Postman-specific APIs that ar
 ````html
 // Postman Visualizer: PyPNM-CMTS/ServingGroup/Upstream/OFDMA/PreEqualization/Results/basic
 // Last Update: 2026-02-28 14:02:00 MST
+// Visual Constraints: Follow canonical visual rules in CODING_AGENTS.md.
 
 const response = pm.response.json();
 
@@ -168,6 +169,16 @@ function buildPayload(r) {
       const rawStats = analysis.signal_statistics || {};
       const gd = normalizeGroupDelay(cv.group_delay);
       const gdStats = gd.length ? computeStats(gd) : null;
+      const gdPoints = [];
+      if (gd.length && freqHzList.length) {
+        const limGd = Math.min(gd.length, freqHzList.length);
+        for (let i = 0; i < limGd; i += 1) {
+          const fHz = n(freqHzList[i]);
+          const y = n(gd[i]);
+          if (fHz == null || y == null) continue;
+          gdPoints.push({ x: fHz / 1e6, y });
+        }
+      }
       const spacingHz = n(analysis.subcarrier_spacing) || 0;
       const windowKey = [Math.round(startMHz*1000)/1000, Math.round(endMHz*1000)/1000, Math.round(spacingHz), points.length].join('|');
       const echo = (analysis.echo && analysis.echo.report) || {};
@@ -184,8 +195,8 @@ function buildPayload(r) {
         channel_id: chanId,
         service_group_id: sgId,
         mac_address: mac,
-        system_model: sys && sys.MODEL ? sys.MODEL : 'LCPET-3',
-        system_sw: sys && sys.SW_REV ? sys.SW_REV : '1.0.0',
+        system_model: sys && sys.MODEL ? sys.MODEL : 'N/A',
+        system_sw: sys && sys.SW_REV ? sys.SW_REV : 'N/A',
         sysdescr_hover: sysDescrSummary(sys) || 'No system_description available',
         status,
         message: modem.message || ((pre.stage_messages || {}).precheck) || '',
@@ -206,7 +217,7 @@ function buildPayload(r) {
         est_chart_id: 'ce-est-' + chIndex + '-' + mIndex,
         chan_est_points: chanEstPoints,
         gd_chart_id: 'ce-gd-' + chIndex + '-' + mIndex,
-        gd_points: gd.length ? gd.map((v, i) => ({ x: i, y: v })) : [],
+        gd_points: gdPoints,
         gd_avg: gdStats ? fmtn(gdStats.avg, 4) : 'N/A',
         gd_p2p: gdStats && gdStats.min != null && gdStats.max != null ? fmtn(gdStats.max - gdStats.min, 4) : 'N/A',
         echo_count: echoes.length,
@@ -287,8 +298,8 @@ const template = `
 <style>
   :root {
     color-scheme: light dark;
-    --bg: #0b1222; --panel: rgba(255,255,255,0.04); --panel2: rgba(255,255,255,0.05);
-    --line: rgba(148,163,184,0.25); --text: #e5e7eb; --muted: #94a3b8;
+    --bg: #141821; --panel: #1b2332; --panel2: #202938;
+    --line: rgba(255,255,255,0.09); --text: #e7edf8; --muted: #dbe3ff;
     --green: #16a34a; --red: #ef4444;
   }
   @media (prefers-color-scheme: light) {
@@ -444,7 +455,7 @@ const template = `
           }
           if (row && row.gd_points && row.gd_points.length) {
             const gd=document.getElementById(row.gd_chart_id);
-            createLineChart(gd,[{label:'GD',data:row.gd_points,parsing:false,pointRadius:0,borderWidth:1.4,tension:0,borderColor:palette[i%palette.length]}],null,'Index','Group Delay');
+            createLineChart(gd,[{label:'GD',data:row.gd_points,parsing:false,pointRadius:0,borderWidth:1.4,tension:0,borderColor:palette[i%palette.length]}],null,'MHz','Group Delay');
           }
         });
       });