Sidebar: Quellen+Feedback-Buttons mit Lucide-Icons + kuerzerem Text

Quellen verwalten -> Quellen (mit database-Icon)
Feedback senden  -> Feedback (mit message-square-Icon)
Tooltip behaelt den vollen Text fuer Mouseover.

src/static/dashboard.html

@@ -123,8 +123,14 @@
                 <div id="archived-incidents" aria-live="polite" style="display:none;"></div>
             </div>
             <div class="sidebar-sources-link">
-                <button class="btn btn-secondary btn-full btn-small" onclick="App.openSourceManagement()">Quellen verwalten</button>
-                <button class="btn btn-secondary btn-full btn-small sidebar-feedback-btn" onclick="App.openFeedback()">Feedback senden</button>
+                <button class="btn btn-secondary btn-full btn-small" onclick="App.openSourceManagement()" title="Quellen verwalten">
+                    <svg xmlns="http://www.w3.org/2000/svg" width="14" height="14" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round" aria-hidden="true"><ellipse cx="12" cy="5" rx="9" ry="3"/><path d="M3 5v14c0 1.66 4.03 3 9 3s9-1.34 9-3V5"/><path d="M3 12c0 1.66 4.03 3 9 3s9-1.34 9-3"/></svg>
+                    <span>Quellen</span>
+                </button>
+                <button class="btn btn-secondary btn-full btn-small sidebar-feedback-btn" onclick="App.openFeedback()" title="Feedback senden">
+                    <svg xmlns="http://www.w3.org/2000/svg" width="14" height="14" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round" aria-hidden="true"><path d="M21 15a2 2 0 0 1-2 2H7l-4 4V5a2 2 0 0 1 2-2h14a2 2 0 0 1 2 2z"/></svg>
+                    <span>Feedback</span>
+                </button>
                 <!-- Tutorial-Einstieg temporaer deaktiviert (Ueberarbeitung) - reaktivieren durch Entfernen der Kommentarzeichen:
                 <button class="btn btn-secondary btn-full btn-small" onclick="Tutorial.start()" title="Interaktiven Rundgang starten">Rundgang starten</button>
                 -->