feat(admin): standalone Projects page + per-project asset manager

- content-svc: GET /v1/projects (browse/search all projects across containers,
  paginated, admin) returning template name/slug + AE status; project_assets
  table (mig 23) + entity; GET/POST/DELETE /v1/projects/{id}/assets
- /admin/projects: searchable, paginated list of every renderable project with
  thumbnail, template, aspect/resolution, AE-file + publish status
- ProjectAssets component: list/upload/delete named footage/image/audio/font
  files per project (reused in the projects page; AE file upload alongside)
- nav + fa/en "Projects" label

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

services/content/FlatRender.ContentSvc/Models/Responses/Responses.cs

@@ -134,6 +134,23 @@ public record ProjectResponse(
     string RenderAepComp
 );
 
+public record ProjectListItemResponse(
+    Guid Id,
+    Guid ContainerId,
+    string ContainerName,
+    string ContainerSlug,
+    string Name,
+    string? Image,
+    string? Aspect,
+    string Resolution,
+    string? AepFileUrl,
+    string RenderAepComp,
+    bool IsPublished,
+    int Sort
+);
+
+public record ProjectAssetResponse(Guid Id, Guid ProjectId, string Name, string Kind, string Url, long? SizeBytes, int Sort);
+
 public record ProjectDetailResponse(
     Guid Id,
     Guid ContainerId,