fix: ask_user_choice Short-Poll, Freitext-Option, Stop-Kontext-Fix

- Long-Poll durch Short-Poll ersetzt (MCP-Server pollt jede Sekunde statt einer blockierenden HTTP-Anfrage)
- Expliziter Lambda-Rückgabetyp Task<IResult> für ASP.NET Minimal API Endpoints (behebt 200 empty body Bug)
- Freitext-Option bei Choice-Buttons ("Eigene Antwort…") für freie User-Eingabe
- Stop während ask_user_choice markiert Chain als awaiting_user_choice statt stopped (Kontext bleibt erhalten)
- ask_user_choice System-Prompt-Instruktion breiter formuliert (Quiz, Multiple-Choice etc.)
- Text wird jetzt immer in DB gespeichert, auch bei ask_user_choice
- Key-Check Model auf claude-haiku-4-5 geändert

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

wwwroot/css/chat.css

@@ -1280,6 +1280,80 @@
   color: var(--muted);
 }
 
+/* Freitext-Option */
+.choice-custom {
+  margin-top: var(--badge-spacing);
+}
+
+.choice-custom-toggle {
+  font-size: 0.85em;
+  color: var(--muted);
+  text-decoration: none;
+}
+
+.choice-custom-toggle:hover {
+  color: var(--primary);
+}
+
+.choice-custom-row {
+  display: none;
+  gap: var(--badge-spacing);
+  align-items: center;
+  margin-top: var(--badge-spacing);
+}
+
+.choice-custom-open .choice-custom-toggle {
+  display: none;
+}
+
+.choice-custom-open .choice-custom-row {
+  display: flex;
+}
+
+.choice-custom-input {
+  flex: 1;
+  border: var(--border-width) solid var(--f1-border);
+  border-radius: var(--border-radius);
+  background: var(--f1-bg);
+  color: var(--f1-text);
+  padding: 0.3em 0.6em;
+  font-size: 0.9em;
+}
+
+.choice-custom-input:focus {
+  border-color: var(--primary);
+  outline: none;
+}
+
+.choice-custom-send {
+  border: var(--border-width) solid var(--primary);
+  border-radius: var(--border-radius);
+  background: transparent;
+  color: var(--primary);
+  cursor: pointer;
+  padding: 0.3em 0.6em;
+  font-size: 0.9em;
+}
+
+.choice-custom-send:hover {
+  background: var(--primary);
+  color: var(--f1-bg);
+}
+
+.choice-answered .choice-custom {
+  display: none;
+}
+
+.choice-answered .choice-custom.has-answer {
+  display: block;
+}
+
+.choice-custom-answer {
+  font-size: 0.85em;
+  color: var(--primary);
+  font-style: italic;
+}
+
 .inline-choice-block {
   margin: var(--gap) 0;
   padding: var(--gap);

wwwroot/js/bubbles.js

@@ -215,6 +215,48 @@ function _createChoiceBubble(opts) {
   }
   div.appendChild(buttonsDiv);
 
+  // Freitext-Option (nur wenn noch nicht beantwortet)
+  if (!answered) {
+    const customDiv = document.createElement('div');
+    customDiv.className = 'choice-custom';
+
+    const toggleLink = document.createElement('a');
+    toggleLink.className = 'choice-custom-toggle';
+    toggleLink.href = '#';
+    toggleLink.textContent = 'Eigene Antwort…';
+    toggleLink.addEventListener('click', function(e) {
+      e.preventDefault();
+      customDiv.classList.add('choice-custom-open');
+      customDiv.querySelector('.choice-custom-input').focus();
+    });
+    customDiv.appendChild(toggleLink);
+
+    const inputRow = document.createElement('div');
+    inputRow.className = 'choice-custom-row';
+
+    const input = document.createElement('input');
+    input.type = 'text';
+    input.className = 'choice-custom-input';
+    input.placeholder = 'Eigene Antwort eingeben…';
+
+    var sendCustom = function() {
+      var text = input.value.trim();
+      if (!text) return;
+      handleChoiceClick(opts.toolCallId, text, div);
+    };
+    input.addEventListener('keydown', function(e) { if (e.key === 'Enter') sendCustom(); });
+
+    var sendBtn = document.createElement('button');
+    sendBtn.className = 'choice-custom-send';
+    sendBtn.textContent = '↵';
+    sendBtn.addEventListener('click', sendCustom);
+
+    inputRow.appendChild(input);
+    inputRow.appendChild(sendBtn);
+    customDiv.appendChild(inputRow);
+    div.appendChild(customDiv);
+  }
+
   if (opts.timestamp) _addTimestamp(div, opts.timestamp);
   return div;
 }

wwwroot/js/chat.js

@@ -415,14 +415,28 @@ async function sendMessageDirect(text) {
 async function handleChoiceClick(toolCallId, choice, bubbleDiv) {
   // Buttons deaktivieren und gewählte Option markieren
   const buttons = bubbleDiv.querySelectorAll('.choice-btn');
+  var matchedButton = false;
   buttons.forEach(btn => {
     btn.disabled = true;
     if (btn.textContent === choice) {
       btn.classList.add('choice-selected');
+      matchedButton = true;
     } else {
       btn.classList.add('choice-unselected');
     }
   });
+  // Freitext-Antwort: Keine der Buttons matched → Antwort als Text anzeigen
+  if (!matchedButton) {
+    var customDiv = bubbleDiv.querySelector('.choice-custom');
+    if (customDiv) {
+      customDiv.innerHTML = '';
+      customDiv.classList.add('has-answer');
+      var answerSpan = document.createElement('span');
+      answerSpan.className = 'choice-custom-answer';
+      answerSpan.textContent = '↳ ' + choice;
+      customDiv.appendChild(answerSpan);
+    }
+  }
   bubbleDiv.classList.add('choice-answered');
 
   // CLI-Modus: Antwort über internen Endpoint an MCP-Server weiterleiten (CLI läuft weiter)