Add processor heartbeat management and improve health check functionality

- Introduced processor heartbeat configuration in environment variables and Docker setup.
- Implemented heartbeat publishing in the processor worker.
- Enhanced health check endpoint to include processor availability status.
- Updated frontend components to handle processor unavailability messages.
- Added legacy return functionality in the upload panel.

www/_js/rus-ecom-240621.js

@@ -304,6 +304,34 @@ function launchFaceAi() {
 	return false;
 }
 
+function clearLegacyLoadingState() {
+	$("body").removeClass("loading");
+}
+
+function shouldClearLegacyLoadingOnRestore(event) {
+	if (event && event.persisted) {
+		return true;
+	}
+
+	if (window.performance && typeof window.performance.getEntriesByType === "function") {
+		var entries = window.performance.getEntriesByType("navigation");
+		if (entries && entries.length && entries[0].type === "back_forward") {
+			return true;
+		}
+	}
+
+	return false;
+}
+
+function restoreLegacyPageAfterHistoryNavigation(event) {
+	if (!shouldClearLegacyLoadingOnRestore(event)) {
+		return;
+	}
+
+	clearLegacyLoadingState();
+	logFaceAiDebug("Cleared legacy loading state after history navigation");
+}
+
 function initFaceAiRaceSearchButton() {
 	var select = $("#tipoPuntoFoto");
 	if (!select.length || $("#faceaiLaunchButton").length || !faceAiFeatureEnabled()) {
@@ -529,11 +557,16 @@ function goPage()
 }
 
 $(function() {
+	clearLegacyLoadingState();
 	initFaceAiRaceSearchButton();
 	initFaceAiErrorModal();
 	logFaceAiDebug("Legacy race page ready");
 });
 
+if (window.addEventListener) {
+	window.addEventListener("pageshow", restoreLegacyPageAfterHistoryNavigation);
+}
+