i18n(ar): keep values whole in right-to-left text

Fixes from the Arabic screenshot review:

- t() isolates every interpolated value in RTL locales (U+2068…U+2069), so
  a time (10/28 09:00 UTC), a code or an English name keeps its order inside
  an Arabic sentence; coordinates (30.326° ش) are isolated too. No-op in
  left-to-right languages.
- The cockpit position readout reads right to left again now that its
  coordinates are isolated; gauges, tapes and roll counters stay LTR.
- The start window's arrows point along the reading direction; FM seek and
  the glyph-only mini transport stay left to right, the worded PREV / PLAY /
  NEXT row follows the page; the Bhote Koshi clock stays a number.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

src/layers/firms/model.js

@@ -1,5 +1,5 @@
 import * as Cesium from 'cesium';
-import { formatNumber, t } from '../../i18n/index.js';
+import { formatNumber, isolate, t } from '../../i18n/index.js';
 import {
   satelliteShortName,
   fireDetectionKey,
@@ -513,7 +513,7 @@ export function createModel({
       lon >= 0
         ? t('{value}°E', { value: amount(lon) })
         : t('{value}°W', { value: amount(lon) });
-    return `${latPart} ${lonPart}`;
+    return `${isolate(latPart)} ${isolate(lonPart)}`;
   }
 
   /** Millisecond delta → "<1h" / "Xh" / "Xd", or '' for invalid input. */