feat(ui): add web search page and preview-before-save flow

- /search shows 'Im Internet suchen' CTA when no local hits or always after search
- /search/web lists SearXNG hits with domain pill and snippet
- /preview loads recipe via preview endpoint and shows unified RecipeView with banner
- Save button imports via POST and navigates to the saved recipe

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

src/routes/search/+page.svelte

@@ -48,7 +48,9 @@
 {:else if searched && hits.length === 0}
   <section class="empty">
     <p>Kein Rezept im Bestand für „{query}".</p>
-    <p class="hint">Bald: Internet durchsuchen.</p>
+    <a class="web-btn" href={`/search/web?q=${encodeURIComponent(query)}`}>
+      🌐 Im Internet suchen
+    </a>
   </section>
 {:else if hits.length > 0}
   <ul class="hits">
@@ -77,7 +79,11 @@
     {/each}
   </ul>
   {#if canWebSearch}
-    <p class="web-hint muted">Weitersuchen im Internet — Phase 4.</p>
+    <div class="web-cta">
+      <a class="web-btn" href={`/search/web?q=${encodeURIComponent(query)}`}>
+        🌐 Im Internet weitersuchen
+      </a>
+    </div>
   {/if}
 {/if}
 
@@ -116,10 +122,6 @@
     text-align: center;
     margin-top: 2rem;
   }
-  .hint {
-    color: #888;
-    font-size: 0.9rem;
-  }
   .hits {
     list-style: none;
     padding: 0;
@@ -169,7 +171,21 @@
     font-size: 0.8rem;
     flex-wrap: wrap;
   }
-  .web-hint {
+  .web-cta {
+    margin-top: 1.25rem;
+    text-align: center;
+  }
+  .web-btn {
+    display: inline-block;
+    padding: 0.8rem 1.25rem;
+    background: #2b6a3d;
+    color: white;
+    text-decoration: none;
+    border-radius: 10px;
+    font-size: 1rem;
+    min-height: 48px;
+  }
+  .empty .web-btn {
     margin-top: 1rem;
   }
 </style>