feat(ui): add minimal homepage with search input

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

src/routes/+page.svelte

@@ -1,2 +1,58 @@
+<script lang="ts">
+  let query = '';
+</script>
+
+<main>
   <h1>Kochwas</h1>
-<p>Coming soon.</p>
+  <form method="GET" action="/search">
+    <input
+      type="search"
+      name="q"
+      bind:value={query}
+      placeholder="Rezept suchen…"
+      autocomplete="off"
+      inputmode="search"
+    />
+    <button type="submit">Suchen</button>
+  </form>
+  <p class="muted">Phase 1: Foundations — Suche folgt in Phase 3.</p>
+</main>
+
+<style>
+  main {
+    max-width: 640px;
+    margin: 4rem auto;
+    padding: 0 1rem;
+    font-family: system-ui, -apple-system, sans-serif;
+  }
+  h1 {
+    text-align: center;
+    font-size: 3rem;
+    margin-bottom: 2rem;
+  }
+  form {
+    display: flex;
+    gap: 0.5rem;
+  }
+  input {
+    flex: 1;
+    padding: 0.75rem 1rem;
+    font-size: 1.1rem;
+    border: 1px solid #bbb;
+    border-radius: 8px;
+  }
+  button {
+    padding: 0.75rem 1.25rem;
+    font-size: 1.1rem;
+    border-radius: 8px;
+    border: 0;
+    background: #2b6a3d;
+    color: white;
+  }
+  .muted {
+    color: #888;
+    font-size: 0.9rem;
+    text-align: center;
+    margin-top: 2rem;
+  }
+</style>