feat(editor): Sektionsueberschriften in IngredientRow + Insert-Button

DraftIng bekommt section_heading: string | null. IngredientRow
rendert davor einen Fade-in-Insert-Button (null) oder ein Heading-
Input mit Entfernen-Button (string). Props onaddSection/onremoveSection
ergaenzt; Styles an bestehendem Block angehaengt.

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

src/lib/components/IngredientRow.svelte

@@ -1,5 +1,5 @@
 <script lang="ts">
-  import { Trash2, ChevronUp, ChevronDown } from 'lucide-svelte';
+  import { Trash2, ChevronUp, ChevronDown, Plus, X } from 'lucide-svelte';
   import type { DraftIng } from './recipe-editor-types';
 
   type Props = {
@@ -8,11 +8,39 @@
     total: number;
     onmove: (dir: -1 | 1) => void;
     onremove: () => void;
+    onaddSection: () => void;
+    onremoveSection: () => void;
   };
 
-  let { ing, idx, total, onmove, onremove }: Props = $props();
+  let { ing, idx, total, onmove, onremove, onaddSection, onremoveSection }: Props = $props();
 </script>
 
+{#if ing.section_heading === null}
+  <li class="section-insert">
+    <button type="button" class="add-section" onclick={onaddSection}>
+      <Plus size={12} strokeWidth={2.5} />
+      <span>Abschnitt hinzufügen</span>
+    </button>
+  </li>
+{:else}
+  <li class="section-heading-row">
+    <input
+      class="section-heading"
+      type="text"
+      bind:value={ing.section_heading}
+      placeholder='Sektion, z. B. „Für den Teig"'
+      aria-label="Sektionsüberschrift"
+    />
+    <button
+      type="button"
+      class="section-remove"
+      aria-label="Sektion entfernen"
+      onclick={onremoveSection}
+    >
+      <X size={14} strokeWidth={2.5} />
+    </button>
+  </li>
+{/if}
 <li class="ing-row">
   <div class="move">
     <button
@@ -126,4 +154,66 @@
       grid-area: del;
     }
   }
+  .section-insert {
+    display: flex;
+    justify-content: center;
+    list-style: none;
+    margin: -0.2rem 0 0.1rem;
+    opacity: 0;
+    transition: opacity 0.15s;
+  }
+  .ing-list:hover .section-insert,
+  .section-insert:focus-within {
+    opacity: 1;
+  }
+  .add-section {
+    display: inline-flex;
+    align-items: center;
+    gap: 0.25rem;
+    padding: 0.2rem 0.55rem;
+    border: 1px dashed #cfd9d1;
+    background: white;
+    color: #2b6a3d;
+    border-radius: 999px;
+    cursor: pointer;
+    font-size: 0.75rem;
+    font-family: inherit;
+  }
+  .add-section:hover {
+    background: #f4f8f5;
+  }
+  .section-heading-row {
+    display: grid;
+    grid-template-columns: 1fr 32px;
+    gap: 0.35rem;
+    list-style: none;
+    margin-top: 0.4rem;
+  }
+  .section-heading {
+    padding: 0.45rem 0.7rem;
+    border: 1px solid #cfd9d1;
+    border-radius: 8px;
+    font-size: 0.95rem;
+    font-weight: 600;
+    color: #2b6a3d;
+    font-family: inherit;
+    background: #f4f8f5;
+  }
+  .section-remove {
+    width: 32px;
+    height: 38px;
+    border: 1px solid #cfd9d1;
+    background: white;
+    border-radius: 8px;
+    color: #666;
+    cursor: pointer;
+    display: inline-flex;
+    align-items: center;
+    justify-content: center;
+  }
+  .section-remove:hover {
+    background: #fdf3f3;
+    border-color: #f1b4b4;
+    color: #c53030;
+  }
 </style>

src/lib/components/recipe-editor-types.ts

@@ -3,6 +3,7 @@ export type DraftIng = {
   unit: string;
   name: string;
   note: string;
+  section_heading: string | null;
 };
 
 export type DraftStep = { text: string };