refactor: consolidate project structure by migrating authentication, identity, and shared UI components while removing legacy Web Client files.

src/NexusReader.Infrastructure/Persistence/AppDbContext.cs

@@ -1,15 +1,17 @@
+using Microsoft.AspNetCore.Identity.EntityFrameworkCore;
 using Microsoft.EntityFrameworkCore;
 using NexusReader.Domain.Entities;
 
 namespace NexusReader.Infrastructure.Persistence;
 
-public class AppDbContext : DbContext
+public class AppDbContext : IdentityDbContext<NexusUser>
 {
     public AppDbContext(DbContextOptions<AppDbContext> options) : base(options)
     {
     }
 
     public DbSet<SemanticKnowledgeCache> SemanticKnowledgeCache => Set<SemanticKnowledgeCache>();
+    public DbSet<Ebook> Ebooks => Set<Ebook>();
 
     protected override void OnModelCreating(ModelBuilder modelBuilder)
     {
@@ -20,5 +22,13 @@ public class AppDbContext : DbContext
             entity.HasKey(e => e.ContentHash);
             entity.HasIndex(e => e.ContentHash).IsUnique();
         });
+
+        modelBuilder.Entity<Ebook>(entity =>
+        {
+            entity.HasOne(e => e.User)
+                .WithMany(u => u.Ebooks)
+                .HasForeignKey(e => e.UserId)
+                .OnDelete(DeleteBehavior.Cascade);
+        });
     }
 }