feature: Phase 22 SEO metadata component for public site

One presentational SeoHead renders the full OG/Twitter/JSON-LD head surface at prerender via typed schema.org builders. Per-medium release schema, config-sourced canonicals, 404 noindex. Zero CMS change.

DeepDrftPublic.Client/Pages/CutDetail.razor

@@ -3,8 +3,7 @@
 @using DeepDrftPublic.Client.Controls
 @using DeepDrftPublic.Client.Services
 @inherits CutDetailBase
-
-<PageTitle>@(ViewModel.Release?.Title ?? "Cut") - DeepDrft</PageTitle>
+@inject SeoOptions Seo
 
 @if (ViewModel.IsLoading)
 {
@@ -37,6 +36,10 @@ else
     var hasYear = release.ReleaseDate is not null;
     var firstTrack = ViewModel.Tracks.Count > 0 ? ViewModel.Tracks[0] : null;
 
+    @* SEO head — fed from the same bridged release + ordered tracks, so the prerender and WASM passes
+       render identical tags (AC6). MusicAlbum/StudioAlbum with the ordered track list (§3.4). *@
+    <SeoHead Model="@SeoModel.ForRelease(Seo, release, ViewModel.Tracks)" />
+
     @* Full-screen content body (Phase 20 Wave 2 §1): the scaffold has no Class param, so a thin wrapper
        carries the min-height. dd-detail-fill keeps the body >= viewport height (below the nav) so the
        ambient visualizer reads full-screen and the site footer is pushed below the fold. *@