CMS Phase 9 Wave 3: Release Archive tab, medium selector, Session/Mix browsers

Renames Genre tab to Release Archive with switch-free medium card group
(Enum.GetValues-driven). Adds MediumFields single dispatch + CutFields/SessionFields/
MixFields per-medium sections embedded by all five upload/edit forms. BatchUpload
enforces single-track invariant for Session/Mix. Adds CmsSessionBrowser (hero-image
upload) and CmsMixBrowser (waveform status + per-row Generate trigger).
ICmsReleaseService/CmsReleaseService wraps api/release endpoints.
Note: medium selector is forward-compat only — API write path pending.

DeepDrftManager/Components/Pages/Tracks/TrackList.razor

@@ -1,6 +1,7 @@
 @page "/tracks"
 @page "/tracks/albums"
 @page "/tracks/genres"
+@page "/tracks/archive"
 @using DeepDrftManager.Services
 @inject CmsTrackBrowserViewModel VM
 @inject ICmsTrackService CmsTrackService
@@ -44,7 +45,7 @@
                     Class="mb-4">
         <MudToggleItem Value="BrowseMode.Tracks">Tracks</MudToggleItem>
         <MudToggleItem Value="BrowseMode.Albums">Releases</MudToggleItem>
-        <MudToggleItem Value="BrowseMode.Genres">Genres</MudToggleItem>
+        <MudToggleItem Value="BrowseMode.Archive">Release Archive</MudToggleItem>
     </MudToggleGroup>
 
     @if (VM.Mode == BrowseMode.Tracks)
@@ -57,8 +58,14 @@
                          IsLoading="VM.AlbumsLoading"
                          OnReleasesChanged="OnAlbumsChanged" />
     }
+    else if (VM.Mode == BrowseMode.Archive)
+    {
+        <ReleaseArchiveBrowser />
+    }
     else
     {
+        @* Genre browse keeps its route (/tracks/genres) but lost its tab to Release Archive (§3.1).
+           Reachable by direct URL; no longer in the toggle group. *@
         <CmsGenreBrowser Genres="VM.Genres"
                          IsLoading="VM.GenresLoading"
                          ExpandedGenre="@VM.ExpandedGenre"
@@ -85,11 +92,11 @@
     protected override async Task OnInitializedAsync()
     {
         var uri = NavigationManager.Uri;
-        var initial = uri.Contains("/tracks/albums", StringComparison.OrdinalIgnoreCase)
-            ? BrowseMode.Albums
-            : uri.Contains("/tracks/genres", StringComparison.OrdinalIgnoreCase)
-                ? BrowseMode.Genres
-                : BrowseMode.Tracks;
+        var initial =
+            uri.Contains("/tracks/albums", StringComparison.OrdinalIgnoreCase) ? BrowseMode.Albums
+            : uri.Contains("/tracks/archive", StringComparison.OrdinalIgnoreCase) ? BrowseMode.Archive
+            : uri.Contains("/tracks/genres", StringComparison.OrdinalIgnoreCase) ? BrowseMode.Genres
+            : BrowseMode.Tracks;
         await VM.SwitchModeAsync(initial);
     }
 
@@ -99,6 +106,7 @@
         var path = mode switch
         {
             BrowseMode.Albums => "/tracks/albums",
+            BrowseMode.Archive => "/tracks/archive",
             BrowseMode.Genres => "/tracks/genres",
             _ => "/tracks"
         };