Color fires from ember to white-hot instead of blue to red

About 90% of detections are under 20 MW, so the old blue and teal
stops painted most of the map in cold colors that do not read as fire.
The ramp now runs ember, red, flame, orange, gold and white-hot at the
same thresholds, each stop lighter than the one below, so the brightest
marks are the strongest fires. The heatmap uses the same colors.

src/data/firmsLabels.test.mjs

@@ -9,16 +9,16 @@ import {
   formatFrpMw,
 } from './firmsLabels.js';
 
-test('FIRMS card accents are the six FRP ramp stops, coldest as the fallback', () => {
-  // Portolan hue order; blue #4a5bd4 … red #d1382a (HAL-675).
-  assert.equal(accentForSeverity('blue'), '74, 91, 212');
-  assert.equal(accentForSeverity('teal'), '57, 160, 168');
-  assert.equal(accentForSeverity('lime'), '201, 207, 74');
-  assert.equal(accentForSeverity('amber'), '242, 177, 52');
-  assert.equal(accentForSeverity('orange'), '232, 114, 44');
-  assert.equal(accentForSeverity('red'), '209, 56, 42');
-  assert.equal(accentForSeverity('yellow'), accentForSeverity('blue'));
-  assert.equal(accentForSeverity('chartreuse'), accentForSeverity('blue'));
+test('FIRMS card accents are the six FRP ramp stops, weakest as the fallback', () => {
+  // Ember #9e2a1b … white-hot #fff3b0, lightness rising with power.
+  assert.equal(accentForSeverity('ember'), '158, 42, 27');
+  assert.equal(accentForSeverity('red'), '210, 64, 31');
+  assert.equal(accentForSeverity('flame'), '240, 106, 40');
+  assert.equal(accentForSeverity('orange'), '251, 154, 46');
+  assert.equal(accentForSeverity('gold'), '253, 200, 74');
+  assert.equal(accentForSeverity('white-hot'), '255, 243, 176');
+  assert.equal(accentForSeverity('blue'), accentForSeverity('ember'));
+  assert.equal(accentForSeverity('chartreuse'), accentForSeverity('ember'));
 });
 
 test('FIRMS power that rounds to 10 MW drops the decimal', () => {