v0.6.0: Sobors.hu parser, HTTP auth, recipe validation, UI polish

- New sobors.hu parser with ingredient groups and section headers
- Incomplete recipe warnings (missing ingredients/instructions)
- Optional HTTP Basic Auth (configurable on settings page)
- Brand text: "Recept" in white, "Importáló" in blue
- Larger logo (36px), favicon using logo_notext.svg

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

app/templates/base.html

@@ -7,6 +7,7 @@
     <link rel="preconnect" href="https://fonts.googleapis.com">
     <link rel="preconnect" href="https://fonts.gstatic.com" crossorigin>
     <link href="https://fonts.googleapis.com/css2?family=Plus+Jakarta+Sans:wght@400;500;600;700&display=swap" rel="stylesheet">
+    <link rel="icon" type="image/svg+xml" href="/assets/logo_notext.svg">
     <style>
         :root {
             --bg: #0d1117;
@@ -53,11 +54,12 @@
             gap: 0.6rem;
             font-size: 1.25rem;
             font-weight: 700;
-            color: var(--accent-light);
             text-decoration: none;
         }
+        nav .brand .brand-white { color: var(--text); }
+        nav .brand .brand-blue { color: var(--accent-light); }
         nav .brand img {
-            height: 28px;
+            height: 36px;
             width: auto;
         }
         nav a {
@@ -212,7 +214,7 @@
     <nav>
         <a href="/" class="brand">
             <img src="/assets/logo.svg" alt="felhom.eu">
-            Recept Importáló
+            <span class="brand-white">Recept</span> <span class="brand-blue">Importáló</span>
         </a>
         <a href="/import" {% if request.path == '/import' %}class="active"{% endif %}>Importálás</a>
         <a href="/settings" {% if request.path == '/settings' %}class="active"{% endif %}>Beállítások</a>