fix(firms): drop the decimal when fire power rounds to 10 MW

A 9.96 MW detection was labeled 10.0 MW because the one-decimal cutoff ran before rounding.

src/data/firmsLabels.test.mjs

@@ -6,6 +6,7 @@ import {
   FIRMS_AMBIENT_COHORT_LIMIT,
   FIRMS_OVERLAY_SOURCE_ID,
   satelliteShortName,
+  formatFrpMw,
 } from './firmsLabels.js';
 
 test('FIRMS formatting helpers retain the shipped severity palette', () => {
@@ -15,6 +16,14 @@ test('FIRMS formatting helpers retain the shipped severity palette', () => {
   assert.equal(accentForSeverity('chartreuse'), accentForSeverity('yellow'));
 });
 
+test('FIRMS power that rounds to 10 MW drops the decimal', () => {
+  assert.equal(formatFrpMw(9.96), '10');
+  assert.equal(formatFrpMw(9.94), '9.9');
+  assert.equal(formatFrpMw(0.8), '0.8');
+  assert.equal(formatFrpMw(1520.27), '1520');
+  assert.equal(formatFrpMw(210.4), '210');
+});
+
 test('FIRMS satellite names retain the three VIIRS abbreviations', () => {
   assert.equal(satelliteShortName('N20'), 'N20');
   assert.equal(satelliteShortName('N21'), 'N21');