refactor(frontend): dedupliziere JS-Code und fixe Bugs

- fix: _oldestLoadedMessageId → _oldestLoadedSortKey (chat.js, chat-page.js)
- move: formatTimestamp nach ui-helpers.js (war _formatTimestamp in msg-actions.js)
- move: _isReviewMessage nach ui-helpers.js (war in history.js)
- add: _getSubAgentMeta + _createSubAgentHeader in ui-helpers.js
- refactor: stream-ui.js + history.js nutzen _createSubAgentHeader
- refactor: flushText() Hilfsfunktion in _renderReviewGroup (history.js)
- refactor: shared-page.js nutzt _mergeConsecutiveAssistantTexts statt eigener Kopie
- refactor: _initCardMenu + _onCardMenuAction Helper in dashboard.js

-53 Zeilen netto

wwwroot/js/ui-helpers.js

@@ -154,6 +154,19 @@ function formatDate(iso) {
   });
 }
 
+function formatTimestamp(isoString) {
+  if (!isoString) return '';
+  var d = new Date(isoString);
+  if (isNaN(d.getTime())) return '';
+  var dd = String(d.getDate()).padStart(2, '0');
+  var mm = String(d.getMonth() + 1).padStart(2, '0');
+  var yyyy = d.getFullYear();
+  var hh = String(d.getHours()).padStart(2, '0');
+  var min = String(d.getMinutes()).padStart(2, '0');
+  var ss = String(d.getSeconds()).padStart(2, '0');
+  return dd + '.' + mm + '.' + yyyy + ' ' + hh + ':' + min + ':' + ss;
+}
+
 // ── Meta Bar ──
 
 function setMeta(text) {
@@ -205,6 +218,40 @@ function removeArchiveLoadButton() {
   btns.forEach(b => b.remove());
 }
 
+// ── Review/Sub-Agent Helpers ──
+
+function _isReviewMessage(content) {
+  return content && (content.startsWith('[Review:') || content.startsWith('[Review-Feedback') || content.startsWith('[Finalizer:') || content.startsWith('[Preparer:'));
+}
+
+/**
+ * Returns { icon, defaultName } for a sub-agent type.
+ * @param {string} agentType - 'preparer', 'finalizer', or 'review'
+ */
+function _getSubAgentMeta(agentType) {
+  if (agentType === 'preparer') return { icon: 'fa-filter', defaultName: 'Vorbereiter-Agent' };
+  if (agentType === 'finalizer') return { icon: 'fa-flag-checkered', defaultName: 'Finalizer-Agent' };
+  return { icon: 'fa-check-circle-o', defaultName: 'Review-Agent' };
+}
+
+/**
+ * Creates a review/sub-agent header element.
+ * @param {string} agentType - 'preparer', 'finalizer', or 'review'
+ * @param {string} agentName - Display name of the agent
+ * @param {object} [extra] - Optional: { round, maxRounds } for review
+ */
+function _createSubAgentHeader(agentType, agentName, extra) {
+  var meta = _getSubAgentMeta(agentType);
+  var header = document.createElement('div');
+  header.className = 'review-header';
+  var html = '<i class="fa ' + meta.icon + '"></i> <strong>' + esc(agentName || meta.defaultName) + '</strong>';
+  if (agentType === 'review' && extra && extra.round) {
+    html += ' <span class="review-round">Runde ' + extra.round + '/' + extra.maxRounds + '</span>';
+  }
+  header.innerHTML = html;
+  return header;
+}
+
 // ── Streamed Elements ──
 
 function removeStreamedElements() {