v2.10.3: smoke follows the theme again

The scatter series still carried large:true, which makes ECharts skip visualMap's
per-point colouring and fall back to its default palette — that is why the smoke was
blue-violet on every theme, clashing badly with amber and nord. Switched to
progressive rendering, which keeps the gradient. Also tightened the deviation range
(0.5 -> 0.35) and widened the opacity span so the beam core reads brighter against
the spread.

Verified by sampling rendered pixels: on amber the chart area contains only warm
oranges (#ffb000 and its darker steps), no blue-violet anywhere; visualMap colours
resolve per theme (dark green, nord frost, amber, solarized cyan).

Author: githubflyideas

static/index.html

@@ -337,12 +337,12 @@
         return html;
       } },
     // 荧光束渐变:贴线的样本 = 炽亮核心,散开的样本渐冷渐暗
-    visualMap: { show: false, type: 'continuous', dimension: 2, min: 0, max: 0.5,
+    visualMap: { show: false, type: 'continuous', dimension: 2, min: 0, max: 0.35,
       seriesIndex: 0,
       inRange: { color: [cssv('--smoke-hot'), cssv('--smoke-mid'), cssv('--smoke-cool')],
-                 opacity: [0.5, 0.10] } },
+                 opacity: [0.55, 0.12] } },
     series: [
-      { type: 'scatter', data: smoke, symbolSize: 2.2, silent: true, large: true },
+      { type: 'scatter', data: smoke, symbolSize: 2.2, silent: true, progressive: 4000, progressiveThreshold: 2000 },
       { type: 'line', data: median, showSymbol: false, silent: true, z: 4,
         lineStyle: { color: phos, width: 7, opacity: 0.10 } },
       { type: 'line', data: median, showSymbol: false,