Update OpenAI API key and enhance app functionality: Replace the OpenAI API key in the .env file for improved access. Refactor app.py to include error handling for missing API keys and implement dark mode functionality with session management. Update README.md to reflect the use of Tailwind CSS via CDN and document the Content Security Policy (CSP) adjustments. Enhance mindmap data loading with a new API endpoint for refreshing data, ensuring better user experience during database connection issues. Update styles and templates for improved UI consistency and responsiveness.

static/js/modules/mindmap.js

@@ -163,7 +163,7 @@ class MindMapVisualization {
       // API-Aufruf mit kürzerem Timeout im Hintergrund durchführen
       try {
         const controller = new AbortController();
-        const timeoutId = setTimeout(() => controller.abort(), 5000); // 5 Sekunden Timeout - reduced from 10
+        const timeoutId = setTimeout(() => controller.abort(), 5000); // 5 Sekunden Timeout
         
         const response = await fetch('/api/mindmap', { 
           signal: controller.signal,
@@ -175,8 +175,55 @@ class MindMapVisualization {
         clearTimeout(timeoutId);
         
         if (!response.ok) {
-          console.warn(`HTTP Fehler: ${response.status}, verwende Standarddaten`);
-          return; // Keep using default data
+          console.warn(`HTTP Fehler: ${response.status}, versuche erneute Verbindung`);
+          
+          // Bei Verbindungsfehler versuchen, die Verbindung neu herzustellen
+          const retryResponse = await fetch('/api/refresh-mindmap', {
+            headers: {
+              'Cache-Control': 'no-cache', 
+              'Pragma': 'no-cache'
+            }
+          });
+          
+          if (!retryResponse.ok) {
+            throw new Error(`Retry failed with status: ${retryResponse.status}`);
+          }
+          
+          const retryData = await retryResponse.json();
+          
+          if (!retryData.success || !retryData.nodes || retryData.nodes.length === 0) {
+            console.warn('Keine Mindmap-Daten nach Neuversuch, verwende weiterhin Standard-Daten.');
+            return; // Keep using default data
+          }
+          
+          // Flache Liste von Knoten und Verbindungen erstellen
+          this.nodes = [];
+          this.links = [];
+          
+          // Knoten direkt übernehmen
+          retryData.nodes.forEach(node => {
+            this.nodes.push({
+              id: node.id,
+              name: node.name,
+              description: node.description || '',
+              thought_count: node.thought_count || 0,
+              color: this.generateColorFromString(node.name),
+            });
+            
+            // Verbindungen hinzufügen
+            if (node.connections && node.connections.length > 0) {
+              node.connections.forEach(conn => {
+                this.links.push({
+                  source: node.id,
+                  target: conn.target
+                });
+              });
+            }
+          });
+          
+          // Visualisierung aktualisieren mit den tatsächlichen Daten
+          this.updateVisualization();
+          return;
         }
         
         const data = await response.json();