Make the image optional for WordPress posts too

Some blog posts just don't have one. WordPressPublisher no longer
rejects publishing a type=blog post without image_url — it uploads
and attaches it as the featured image when present, and simply skips
that step (no featured_media set) otherwise.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

resources/views/livewire/posts/index.blade.php

@@ -27,8 +27,6 @@
                     <td class="p-3">
                         @if ($post->image_url)
                             <img src="{{ $post->image_url }}" alt="" class="w-10 h-10 object-cover rounded">
-                        @elseif ($post->type === 'blog')
-                            <span class="text-xs text-amber-600">missing</span>
                         @else
                             <span class="text-gray-400">—</span>
                         @endif
@@ -118,7 +116,7 @@
 
                 <div>
                     <label class="block text-sm font-medium">
-                        Image URL {{ $type === 'blog' ? '(required to publish to WordPress)' : '(optional)' }}
+                        Image URL (optional{{ $type === 'blog' ? ' — used as the featured image on WordPress if set' : '' }})
                     </label>
                     <input type="url" wire:model="imageUrl" placeholder="https://..." class="w-full border rounded p-2">
                     @error('imageUrl') <span class="text-red-600 text-sm">{{ $message }}</span> @enderror