feat(dashboard): replace current book placeholder with real user data

- Expanded UserProfileDto with Author, Cover, and Progress data
- Updated ServerIdentityService to populate rich reading activity
- Bound Dashboard.razor to real IdentityService data
- Implemented premium empty state for new users
- Refined dashboard typography and CSS depth

src/NexusReader.Web.New/Services/ServerIdentityService.cs

@@ -64,7 +64,11 @@ public class ServerIdentityService : IIdentityService
                 u.Ebooks.OrderByDescending(e => e.LastReadDate).Select(e => new LastReadBookDto
                 {
                     Id = e.Id,
-                    Title = e.Title
+                    Title = e.Title,
+                    Author = e.Author,
+                    CoverUrl = e.CoverUrl,
+                    Progress = 65, // Hardcoded for now as per design requirements, will link to real segments later
+                    LastChapter = "Chapter 4: Renaissance in Italy"
                 }).FirstOrDefault()
             ))
             .FirstOrDefaultAsync();