feat(planner): add onremove prop and Entfernen button to MealActionSheet

Button only renders when onremove callback is provided, keeping the
component usable in read-only contexts without the destructive action.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

frontend/src/lib/planner/MealActionSheet.svelte

@@ -17,9 +17,10 @@
     slot: Slot;
     onswap: () => void;
     oncancel: () => void;
+    onremove?: () => void;
   }
 
-  let { open, slot, onswap, oncancel }: Props = $props();
+  let { open, slot, onswap, oncancel, onremove }: Props = $props();
 
   const meta = $derived.by(() => {
     const parts: string[] = [];
@@ -82,6 +83,16 @@
           ↻ Gericht tauschen
         </button>
 
+        {#if onremove}
+          <button
+            type="button"
+            style="width:100%;background:var(--color-error, #d9534f);border:1px solid var(--color-error, #d9534f);color:#fff;font-family:var(--font-sans);font-size:13px;font-weight:500;border-radius:var(--radius-lg);padding:12px;text-align:center;cursor:pointer"
+            onclick={onremove}
+          >
+            ✕ Gericht entfernen
+          </button>
+        {/if}
+
         {#if slot.recipe}
           <a
             href="/recipes/{slot.recipe.id}/cook"