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/Requests/Requests.cs

@@ -244,6 +244,15 @@ public record UpdateProjectRequest(
 
 // Partial update — only non-null fields are applied, so editing an aspect/resolution
 // never wipes render/colour data that the full UpdateProjectRequest would require.
+public record CreateAssetRequest(
+    string Name,
+    string? Kind,
+    string Url,
+    string? MinioKey,
+    long? SizeBytes,
+    int Sort = 0
+);
+
 public record SetAepRequest(
     string? AepFileUrl,
     string? AepMinioBucket,