[fix](trx-frontend-http): AIS map markers use scheme lead color (--accent-green)

Use --accent-green (the primary/lead accent color) for AIS vessel markers and
tracks instead of a hardcoded or red-based color, so they match the active
buttons and other prominent UI elements for every color scheme.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Signed-off-by: Stan Grams <sjg@haxx.space>

src/trx-client/trx-frontend/trx-frontend-http/assets/web/app.js

@@ -5014,7 +5014,7 @@ function syncSelectedAisTrackVisibility() {
 }
 
 function getAisAccentColor() {
-  return getComputedStyle(document.documentElement).getPropertyValue("--ais-accent").trim() || "#00aacc";
+  return getComputedStyle(document.documentElement).getPropertyValue("--accent-green").trim() || "#c24b1a";
 }
 
 function aisMarkerOptionsFromMessage(msg) {