feat(ui): custom confirmation dialog replacing native window.confirm

Single reusable dialog with a promise-based API: confirmAction({...})
returns Promise<boolean>. Supports title, optional message body,
confirm/cancel labels, and a 'destructive' flag that paints the confirm
button red.

Accessibility: Escape cancels, Enter confirms, confirm button auto-focus,
role=dialog + aria-labelledby, backdrop click = cancel.

Rolled out to: recipe delete, domain remove, profile delete, wishlist
remove. Native confirm() is gone from the codebase.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/routes/wishlist/+page.svelte

@@ -1,6 +1,7 @@
 <script lang="ts">
   import { onMount } from 'svelte';
   import { profileStore } from '$lib/client/profile.svelte';
+  import { confirmAction } from '$lib/client/confirm.svelte';
   import type { WishlistEntry, SortKey } from '$lib/server/wishlist/repository';
 
   let entries = $state<WishlistEntry[]>([]);
@@ -39,7 +40,13 @@
   }
 
   async function remove(entry: WishlistEntry) {
-    if (!confirm(`„${entry.title}" von der Wunschliste entfernen?`)) return;
+    const ok = await confirmAction({
+      title: 'Von der Wunschliste entfernen?',
+      message: `„${entry.title}" wird aus der Wunschliste entfernt. Das Rezept selbst bleibt gespeichert.`,
+      confirmLabel: 'Entfernen',
+      destructive: true
+    });
+    if (!ok) return;
     await fetch(`/api/wishlist/${entry.recipe_id}`, { method: 'DELETE' });
     await load();
   }