feat: enhance canvas functionality with proximity edge handling and improved authentication logging

- Introduced temporary edge styling for proximity connections in the canvas.
- Updated edge synchronization logic to filter out temporary edges during data processing.
- Enhanced authentication logging to provide detailed user identity information when authentication fails.
- Added a new utility function for sanitizing edge handle IDs to ensure compatibility with React Flow.
- Implemented a node handle mapping for proximity connections to streamline edge management.

app/globals.css

@@ -149,4 +149,16 @@
   .react-flow__handle {
     z-index: 50;
   }
-}
+
+  /* Proximity-Vorschaukante (temp) */
+  .react-flow__edge.temp {
+    opacity: 0.9;
+  }
+
+  .react-flow__edge.temp .react-flow__edge-path {
+    stroke: hsl(var(--foreground) / 0.3);
+    stroke-width: 2.5;
+    stroke-dasharray: 8 6;
+    stroke-linecap: round;
+  }
+}