fix(ui): active request card -> real-time QPS-style sparkline; remove pie slice outline

- drawActiveChart: rolling request-rate buffer (window.qpsSeries) sampled ~every 2s from records timestamps, drawn as an area+fine; header shows current active requests + 'reqs / 3s' subtitle; refreshes on the existing 3s paintStats poll
- status pie: remove the hard slice outline (no stroke), clean seamless slices
- active card now consistent with others: big value + subtitle + chart
- deployed (bak .bak.20260811n), server active

internal/gateway/ui/index.html

@@ -767,7 +767,9 @@ async function paintStats() {
     const kpi = $('#kpi-row');
     if (kpi) kpi.innerHTML = `
       <div class="kpi${statsKeyF ? ' kpi-exit' : ''}" title="${statsKeyF ? t('exitKeyView') : ''}" onclick="${statsKeyF ? `renderKeyF('${escAttr(statsKeyF)}')` : ''}">
-        <div class="k-hdr"><span class="k-lab">${t('kpiActive')} <span class="dot"></span></span><span class="okc k-sub">${st.active || 0}</span></div>
+        <div class="k-hdr"><span class="k-lab">${t('kpiActive')} <span class="dot"></span></span></div>
+        <div class="k-val">${st.active || 0}</div>
+        <div class="k-sub">reqs / 3s</div>
         <div class="k-chart"><canvas id="cv-active"></canvas></div>
       </div>
       <div class="kpi">
@@ -871,17 +873,37 @@ function dailyBars(ctx, counts, w, h, color) {
   });
 }
 
+// rolling real-time request-rate buffer (QPS-style sparkline)
+window.qpsSeries = window.qpsSeries || { last: Date.now(), data: [] };
 function drawActiveChart(st) {
   const cv = document.getElementById('cv-active'); if (!cv) return;
   const ctx = cv.getContext('2d');
   const dpr = window.devicePixelRatio || 1;
   const parent = cv.parentElement, rect = parent.getBoundingClientRect();
-  cv.width = rect.width * dpr; cv.height = 86 * dpr; ctx.scale(dpr, dpr);
+  const H = 86;
+  cv.width = rect.width * dpr; cv.height = H * dpr; ctx.scale(dpr, dpr);
   ctx.clearRect(0, 0, cv.width, cv.height);
-  // active count across records window (bucketed per minute) as a sparkline
+  // sample: requests started in the last 3s (approx QPS). Records carry unix-ms time.
+  const qs = window.qpsSeries;
+  const now = Date.now();
   const recs = st.records || [];
-  const col = window.charts && window.charts.active || [];
+  const rate = recs.filter(r => r.time >= now - 3000).length;
-  sparkline(ctx, col, rect.width, 86, '#4fa3d8');
+  if (now - qs.last >= 2000) { qs.last = now; qs.data.push(Math.max(rate, 0)); }
+  if (qs.data.length > 40) qs.data.shift();
+  // grid baseline
+  ctx.strokeStyle = 'var(--line)'; ctx.lineWidth = 1; ctx.beginPath();
+  ctx.moveTo(0, H - 1); ctx.lineTo(rect.width, H - 1); ctx.stroke();
+  // area fill under the line
+  if (qs.data.length > 1) {
+    const max = Math.max.apply(null, qs.data) || 1;
+    const px = i => i / (qs.data.length - 1) * rect.width;
+    const py = v => 2 + (1 - v / max) * (H - 4);
+    ctx.beginPath();
+    qs.data.forEach((v, i) => i ? ctx.lineTo(px(i), py(v)) : ctx.moveTo(px(i), py(v)));
+    ctx.lineTo(rect.width, H); ctx.lineTo(px(0), H); ctx.closePath();
+    ctx.fillStyle = 'rgba(79,163,216,.18)'; ctx.fill();
+    sparkline(ctx, qs.data, rect.width, H, '#4fa3d8');
+  }
 }
 function drawReqsChart(st) {
   const cv = document.getElementById('cv-reqs'); if (!cv) return;
@@ -955,7 +977,6 @@ function drawStatusChart(rows) {
     ctx.closePath();
     ctx.fillStyle = palette[i % palette.length];
     ctx.fill();
-    ctx.strokeStyle = 'var(--card)'; ctx.lineWidth = 1.5; ctx.stroke();
     a0 += sweep;
   });
   // center label = total