Refactor error handling utilities

- Replace `showError` with a more versatile `showToast` utility.
- Add specific toast functions (`showErrorToast`, `showSuccessToast`, etc.) for better message handling.
- Remove `showError.ts` and migrate logic to `showToast.ts` for cleaner structure.
- Update `ErrorBoundary` and `useErrorHandler` to use the new `showToast` functions.

internal_frontend/lib/ui/showError.ts

@@ -1,16 +0,0 @@
-// lib/ui/showError.ts
-import {toast} from "sonner";
-
-export function showError(error: unknown, fallback = "Ein unbekannter Fehler ist aufgetreten") {
-    let message: string;
-
-    if (error instanceof Error) {
-        message = error.message;
-    } else if (typeof error === "string") {
-        message = error;
-    } else {
-        message = fallback;
-    }
-
-    toast.error(message);
-}

internal_frontend/lib/ui/showToast.ts

@@ -0,0 +1,71 @@
+// lib/ui/showToast.ts
+import { toast } from "sonner";
+
+// Generic toast function
+export function showToast(message: string, type: 'success' | 'error' | 'info' | 'warning' = 'info') {
+    const options = {
+        dismissible: true,
+        closeButton: true,
+    };
+
+    switch (type) {
+        case 'success':
+            toast.success(message, options);
+            break;
+        case 'error':
+            toast.error(message, options);
+            break;
+        case 'info':
+            toast.info(message, options);
+            break;
+        case 'warning':
+            toast.warning(message, options);
+            break;
+        default:
+            toast(message, options);
+    }
+}
+
+// Specific toast functions with appropriate error handling
+export function showErrorToast(error: unknown, fallback = "Ein unbekannter Fehler ist aufgetreten") {
+    let message: string;
+
+    if (error instanceof Error) {
+        message = error.message;
+    } else if (typeof error === "string") {
+        message = error;
+    } else {
+        message = fallback;
+    }
+
+    toast.error(message, {
+        dismissible: true,
+        closeButton: true,
+    });
+}
+
+export function showSuccessToast(message: string) {
+    toast.success(message, {
+        dismissible: true,
+        closeButton: true,
+    });
+}
+
+export function showInfoToast(message: string) {
+    toast.info(message, {
+        dismissible: true,
+        closeButton: true,
+    });
+}
+
+export function showWarningToast(message: string) {
+    toast.warning(message, {
+        dismissible: true,
+        closeButton: true,
+    });
+}
+
+// Backward compatibility - keep the original showError function
+export function showError(error: unknown, fallback = "Ein unbekannter Fehler ist aufgetreten") {
+    showErrorToast(error, fallback);
+}