Add email templates, page layouts, and shop themes (template system)

- E-Mail-Templates: DB-gespeicherte HTML-Templates mit {{placeholder}}-System,
  Admin-UI zum Bearbeiten von Betreff und Body, alle 4 Mailables aktualisiert
- Seiten-Layouts: 4 Layouts für CMS-Seiten (Standard, Sidebar, Volle Breite, Landing),
  Layout-Auswahl im Admin-Formular
- Shop-Themes: 5 Farbthemen via CSS-Variablen, Picker in Einstellungen
- Deployment: EmailTemplateSeeder wird automatisch beim Deploy ausgeführt

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

resources/views/shop/page.blade.php

@@ -1,11 +1,59 @@
+@php $layout = $page->layout ?? 'default'; @endphp
+
+@if($layout === 'landing')
+<!DOCTYPE html>
+<html lang="de">
+<head>
+    <meta charset="UTF-8">
+    <meta name="viewport" content="width=device-width, initial-scale=1.0">
+    <title>{{ $page->meta_title ?: $page->title }}</title>
+    <meta name="description" content="{{ $page->meta_description }}">
+    @vite(['resources/css/app.css', 'resources/js/app.js'])
+</head>
+<body class="bg-gray-50 text-gray-800">
+    <div class="prose max-w-none text-gray-700 p-8">
+        {!! $page->content !!}
+    </div>
+</body>
+</html>
+@else
 @extends('layouts.shop')
 @section('title', $page->meta_title ?: $page->title)
 @section('meta_description', $page->meta_description)
 @section('content')
-<div class="max-w-3xl mx-auto">
+
+@switch($layout)
+
+    @case('full')
     <h1 class="text-3xl font-bold mb-6">{{ $page->title }}</h1>
     <div class="prose max-w-none text-gray-700">
         {!! $page->content !!}
     </div>
-</div>
+    @break
+
+    @case('sidebar')
+    <div class="grid grid-cols-1 lg:grid-cols-3 gap-8">
+        <div class="lg:col-span-2">
+            <h1 class="text-3xl font-bold mb-6">{{ $page->title }}</h1>
+            <div class="prose max-w-none text-gray-700">
+                {!! $page->content !!}
+            </div>
+        </div>
+        <aside class="space-y-6">
+            @include('shop.partials._sidebar')
+        </aside>
+    </div>
+    @break
+
+    @default
+    <div class="max-w-3xl mx-auto">
+        <h1 class="text-3xl font-bold mb-6">{{ $page->title }}</h1>
+        <div class="prose max-w-none text-gray-700">
+            {!! $page->content !!}
+        </div>
+    </div>
+
+@endswitch
+
 @endsection
+@endif

resources/views/shop/partials/_sidebar.blade.php

@@ -0,0 +1,39 @@
+{{-- Kategorien --}}
+@php
+    $sidebarCats = \App\Models\Category::whereNull('parent_id')->where('active', true)->orderBy('sort_order')->get();
+    $sidebarBlogPages = \App\Models\Page::where('type','blog')->where('published',true)->orderByDesc('published_at')->limit(5)->get();
+@endphp
+
+@if($sidebarCats->count())
+<div class="bg-white rounded shadow p-4">
+    <h3 class="font-semibold mb-3 text-gray-800">Kategorien</h3>
+    <ul class="space-y-1">
+        @foreach($sidebarCats as $cat)
+        <li>
+            <a href="{{ route('shop.category', $cat->slug) }}"
+               class="block px-2 py-1.5 rounded text-sm text-gray-700 hover-primary transition">
+                {{ $cat->name }}
+            </a>
+        </li>
+        @endforeach
+    </ul>
+</div>
+@endif
+
+@if($sidebarBlogPages->count())
+<div class="bg-white rounded shadow p-4">
+    <h3 class="font-semibold mb-3 text-gray-800">Aktuelle Beiträge</h3>
+    <ul class="space-y-3">
+        @foreach($sidebarBlogPages as $bp)
+        <li>
+            <a href="{{ route('page', $bp->slug) }}" class="text-sm text-primary hover:underline">
+                {{ $bp->title }}
+            </a>
+            @if($bp->published_at)
+            <p class="text-xs text-gray-400">{{ $bp->published_at->format('d.m.Y') }}</p>
+            @endif
+        </li>
+        @endforeach
+    </ul>
+</div>
+@endif