feat: Reply/Zitat-Feature für Chat-Nachrichten

- Reply-Button (Hover) auf jeder User/Assistant-Nachricht
- Reply-Preview-Leiste über dem Input-Feld (mit Timestamp, Rolle, Text-Preview)
- Beim Senden: Zitat als Kontext-Block vorangestellt (> [Zitat: HH:MM, Role]:)
- User-Nachrichten parsen Zitat-Blöcke als visuelle Quote-Elemente (blaue Borderlinie)
- Timestamp-basierte Referenzierung (HH:MM oder DD.MM. HH:MM)
- clearReply() bei Chat-Clear, Navigation und Destroy

wwwroot/js/ui.js

@@ -33,10 +33,64 @@ function truncate(s, max) {
   return s && s.length > max ? s.substring(0, max) + '...' : (s || '');
 }
 
+// ── Reply Button ──
+
+function _addReplyButton(div) {
+  const btn = document.createElement('button');
+  btn.className = 'msg-reply-btn icon-btn';
+  btn.innerHTML = '<i class="fa fa-reply"></i>';
+  btn.title = 'Antworten';
+  btn.addEventListener('click', (e) => {
+    e.stopPropagation();
+    // Nur den eigentlichen Nachrichten-Text holen (ohne Reply-Button-Text)
+    const clone = div.cloneNode(true);
+    clone.querySelectorAll('.msg-reply-btn, .attachment-indicator, .reply-quote').forEach(el => el.remove());
+    const text = clone.textContent.trim();
+    setReply({
+      role: div.dataset.role,
+      timestamp: div.dataset.timestamp || '',
+      text
+    });
+  });
+  div.appendChild(btn);
+}
+
 // ── Message Bubbles ──
 
 function renderUserContent(container, text) {
   const raw = (text || '').trim();
+
+  // Reply-Zitat erkennen und als visuellen Block rendern
+  // Format: > [Zitat: HH:MM, Role]:\n> text...\n\nrest
+  const quoteMatch = raw.match(/^> \[Zitat: ([^\]]+)\]:\n((?:> .*\n?)*)\n*([\s\S]*)$/);
+  if (quoteMatch) {
+    const quoteMeta = quoteMatch[1]; // z.B. "14:32, Assistant"
+    const quoteBody = quoteMatch[2].replace(/^> /gm, '').trim();
+    const restText = quoteMatch[3].trim();
+
+    const quoteEl = document.createElement('div');
+    quoteEl.className = 'reply-quote';
+    const metaEl = document.createElement('div');
+    metaEl.className = 'reply-quote-meta';
+    metaEl.innerHTML = '<i class="fa fa-reply"></i> ' + esc(quoteMeta);
+    quoteEl.appendChild(metaEl);
+    const bodyEl = document.createElement('div');
+    bodyEl.className = 'reply-quote-text';
+    bodyEl.textContent = truncate(quoteBody, 200);
+    quoteEl.appendChild(bodyEl);
+    container.appendChild(quoteEl);
+
+    // Rest als normalen Text weiterverarbeiten
+    if (restText) {
+      _renderUserTextContent(container, restText);
+    }
+    return;
+  }
+
+  _renderUserTextContent(container, raw);
+}
+
+function _renderUserTextContent(container, raw) {
   // [Datei: path] oder [Datei: path:1-10] erkennen
   const pattern = /\[Datei: ([^\]]+)\]/g;
   let last = 0;
@@ -75,19 +129,25 @@ function renderUserContent(container, text) {
   container.appendChild(frag);
 }
 
-function addUserBubble(text, streamed = false) {
+function addUserBubble(text, streamed = false, timestamp = '') {
   const div = document.createElement('div');
   div.className = 'msg user';
+  div.dataset.role = 'user';
+  div.dataset.timestamp = timestamp || new Date().toISOString();
   if (streamed) div.classList.add('streamed');
   renderUserContent(div, text);
+  _addReplyButton(div);
   chatEl().appendChild(div);
   scrollDown();
 }
 
-function addAssistantBubble(text) {
+function addAssistantBubble(text, timestamp = '') {
   const div = document.createElement('div');
   div.className = 'msg assistant markdown';
+  div.dataset.role = 'assistant';
+  div.dataset.timestamp = timestamp || new Date().toISOString();
   div.innerHTML = renderMarkdown(text);
+  _addReplyButton(div);
   chatEl().appendChild(div);
   scrollDown();
   return div;