fix: Fehlendes src-type-display Element im Quellen-Formular ergänzt

Das readonly Input zeigt dem Nutzer den erkannten Quellentyp (RSS-Feed,
Web-Quelle, Telegram) nach der Auto-Erkennung an. Der hidden Select
dient weiterhin als Datenspeicher für saveSource().
Telegram-Pfad setzt jetzt ebenfalls src-type-display.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

src/static/dashboard.html

@@ -603,8 +603,9 @@
                                 </select>
                             </div>
                             <div class="form-group">
-                                <label for="src-type-select">Typ</label>
+                                <label>Typ</label>
-                                <select id="src-type-select">
+                                <input type="text" id="src-type-display" class="input-readonly" readonly>
+                                <select id="src-type-select" style="display:none">
                                     <option value="rss_feed">RSS-Feed</option>
                                     <option value="web_source">Web-Quelle</option>
                                     <option value="telegram_channel">Telegram-Kanal</option>

src/static/js/app.js

@@ -2682,6 +2682,7 @@ const App = {
             };
             document.getElementById('src-name').value = '@' + channelName;
             document.getElementById('src-type-select').value = 'telegram_channel';
+            document.getElementById('src-type-display').value = 'Telegram';
             document.getElementById('src-domain').value = tgUrl;
             document.getElementById('src-rss-url-group').style.display = 'none';
             document.getElementById('src-discovery-result').style.display = 'block';