Attribution: Übermittler aus users.agency_name statt Agentur-Firma

A3 des Umbaus Agentur-Attribution → User-Profil: Eager Loading der
Detailseite/Vorschau lädt user:id,agency_name; die Legacy-Relation
PressRelease::submittingAgency() (Pseudo-Firma type=agency via
owner_user_id) entfällt. Tests decken Verteiler-Fall, Namensgleichheit
und PM ohne Übermittler ab.

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

app/Services/Web/ReleaseDetailPageData.php

@@ -33,6 +33,7 @@ class ReleaseDetailPageData
             ->where('slug', $slug)
             ->with([
                 'company',
+                'user:id,agency_name',
                 'category.translations' => fn ($query) => $query->where('locale', $language),
                 'category.parent.translations' => fn ($query) => $query->where('locale', $language),
                 'images' => fn ($query) => $query->orderByDesc('is_preview')->orderBy('sort_order'),