added fileFetchedAt to TickerPageResponse and updated the Ticker UI to use it as the data currency timestamp for proxied files

lib/api/marianumconnect/queries/get_ticker_page/get_ticker_page_response.dart

@@ -44,6 +44,12 @@ class TickerPageResponse {
   /// when the page has never been published.
   final String? publishedAt;
 
+  /// PROXIED_FILE only: ISO timestamp of the last successful re-fetch of the
+  /// file by the server proxy (`ticker_pages.proxy_last_success_at`) — the
+  /// document's data currency, shown as "Aktualisiert am …" instead of
+  /// [publishedAt]. Null for other kinds / files never fetched yet.
+  final String? fileFetchedAt;
+
   TickerPageResponse({
     required this.schemaVersion,
     this.slug,
@@ -58,6 +64,7 @@ class TickerPageResponse {
     this.hash,
     this.webUrl,
     this.publishedAt,
+    this.fileFetchedAt,
   });
 
   factory TickerPageResponse.fromJson(Map<String, dynamic> json) =>

lib/api/marianumconnect/queries/get_ticker_page/get_ticker_page_response.g.dart

@@ -21,6 +21,7 @@ TickerPageResponse _$TickerPageResponseFromJson(Map<String, dynamic> json) =>
       hash: json['hash'] as String?,
       webUrl: json['webUrl'] as String?,
       publishedAt: json['publishedAt'] as String?,
+      fileFetchedAt: json['fileFetchedAt'] as String?,
     );
 
 Map<String, dynamic> _$TickerPageResponseToJson(TickerPageResponse instance) =>
@@ -38,4 +39,5 @@ Map<String, dynamic> _$TickerPageResponseToJson(TickerPageResponse instance) =>
       'hash': instance.hash,
       'webUrl': instance.webUrl,
       'publishedAt': instance.publishedAt,
+      'fileFetchedAt': instance.fileFetchedAt,
     };