Tag blog posts and sign them with a member

Tags are named in every language and made from the page form; the byline is
the member who signs a post on the site. The public API sends both, filters
posts by tag and lists the tags in use.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

app/Http/Requests/Api/V1/PageRequest.php

@@ -49,6 +49,10 @@ class PageRequest extends FormRequest
             'meta_description' => ['sometimes', 'nullable', new Translatable(max: 160)],
 
             'category_id' => ['sometimes', 'nullable', 'integer', Rule::exists('categories', 'id')->whereNull('deleted_at')],
+            // Who signs it on the site; replaced whole when sent, like the tags.
+            'byline_member_id' => ['sometimes', 'nullable', 'integer', Rule::exists('members', 'id')->whereNull('deleted_at')],
+            'tag_ids' => ['sometimes', 'array'],
+            'tag_ids.*' => ['integer', 'distinct', Rule::exists('tags', 'id')],
             'status' => ['sometimes', Rule::enum(PageStatus::class)],
             'featured_image' => ['sometimes', 'nullable', 'string', 'max:2048'],
             'featured_image_alt' => ['sometimes', 'nullable', new Translatable(max: 255)],