[fix](trx-frontend-http): move escapeMapHtml to global scope in app.js

escapeMapHtml was defined inside the map-core.js IIFE, making it
inaccessible to app.js and plugin files (aprs, ais, vdes, cw, hf-aprs)
that call it from global scope, causing ReferenceError at runtime.

Move the function definition to app.js (global scope), export it via
window.trx, and destructure it in map-core.js like other shared utils.

https://claude.ai/code/session_01RhL8cCcszaguKqoWn5XUxL
Signed-off-by: Claude <noreply@anthropic.com>

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

@@ -35,6 +35,13 @@ function loadSetting(key, fallback) {
     return v !== null ? JSON.parse(v) : fallback;
   } catch(e) { return fallback; }
 }
+function escapeMapHtml(input) {
+  return String(input)
+    .replaceAll("&", "&")
+    .replaceAll("<", "&lt;")
+    .replaceAll(">", "&gt;")
+    .replaceAll("\"", "&quot;");
+}
 
 // --- Authentication ---
 let authRole = null;  // null (not authenticated), "rx" (read-only), or "control" (full access)
@@ -4591,7 +4598,7 @@ Object.defineProperties(window.trx, {
 });
 // -- Shared utility functions --
 Object.assign(window.trx, {
-  saveSetting, loadSetting, showHint, formatFreq, formatFreqForHumans,
+  saveSetting, loadSetting, showHint, escapeMapHtml, formatFreq, formatFreqForHumans,
   formatWavelength, formatBwLabel, formatUptime, formatSigStrength, formatSignal,
   postPath, scheduleUiFrameJob, navigateToTab, rigBadgeColor,
   latLonToMaidenhead, locatorToLatLon, haversineKm, formatDistanceKm,

src/trx-client/trx-frontend/trx-frontend-http/assets/web/map-core.js

@@ -5,7 +5,7 @@
   const T = window.trx;
 
   // Destructure shared utility functions for convenience
-  const { saveSetting, loadSetting, showHint, formatFreq, formatFreqForHumans,
+  const { saveSetting, loadSetting, showHint, escapeMapHtml, formatFreq, formatFreqForHumans,
           postPath, scheduleUiFrameJob, navigateToTab, rigBadgeColor,
           formatUptime, latLonToMaidenhead, locatorToLatLon, haversineKm,
           formatDistanceKm, formatTimeAgo, currentDecodeHistoryRetentionMs,
@@ -2430,14 +2430,6 @@
     });
   }
 
-  function escapeMapHtml(input) {
-    return String(input)
-      .replaceAll("&", "&")
-      .replaceAll("<", "&lt;")
-      .replaceAll(">", "&gt;")
-      .replaceAll("\"", "&quot;");
-  }
-
   function formatDecodeLocatorTime(tsMs) {
     if (!Number.isFinite(tsMs)) return "--:--:--";
     return new Date(tsMs).toLocaleTimeString([], {