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

src/NexusReader.Domain/Entities/Ebook.cs

@@ -0,0 +1,36 @@
+using System.ComponentModel.DataAnnotations;
+using System.ComponentModel.DataAnnotations.Schema;
+
+namespace NexusReader.Domain.Entities;
+
+/// <summary>
+/// Represents an E-book uploaded or owned by a user.
+/// </summary>
+public class Ebook
+{
+    [Key]
+    public Guid Id { get; set; } = Guid.NewGuid();
+
+    [Required]
+    [MaxLength(255)]
+    public string Title { get; set; } = string.Empty;
+
+    [MaxLength(255)]
+    public string Author { get; set; } = "Unknown";
+
+    [Required]
+    public string FilePath { get; set; } = string.Empty;
+
+    public string? CoverUrl { get; set; }
+
+    public DateTime AddedDate { get; set; } = DateTime.UtcNow;
+
+    public DateTime? LastReadDate { get; set; }
+
+    // Relationship to NexusUser
+    [Required]
+    public string UserId { get; set; } = string.Empty;
+
+    [ForeignKey(nameof(UserId))]
+    public NexusUser? User { get; set; }
+}

src/NexusReader.Domain/Entities/NexusUser.cs

@@ -0,0 +1,34 @@
+using Microsoft.AspNetCore.Identity;
+
+namespace NexusReader.Domain.Entities;
+
+/// <summary>
+/// Extended Identity user for the Nexus AI E-Reader SaaS platform.
+/// </summary>
+public class NexusUser : IdentityUser
+{
+    /// <summary>
+    /// Total number of AI tokens allowed for the current billing period.
+    /// </summary>
+    public int AITokenLimit { get; set; }
+
+    /// <summary>
+    /// Number of AI tokens consumed in the current billing period.
+    /// </summary>
+    public int AITokensUsed { get; set; }
+
+    /// <summary>
+    /// Unique identifier for the tenant (SaaS multi-tenancy support).
+    /// </summary>
+    public Guid TenantId { get; set; }
+
+    /// <summary>
+    /// Current subscription plan (e.g., "Free", "Pro", "Enterprise").
+    /// </summary>
+    public string CurrentPlan { get; set; } = "Free";
+
+    /// <summary>
+    /// Collection of e-books owned by the user.
+    /// </summary>
+    public ICollection<Ebook> Ebooks { get; set; } = new List<Ebook>();
+}

src/NexusReader.Domain/NexusReader.Domain.csproj

@@ -1,4 +1,4 @@
-<Project Sdk="Microsoft.NET.Sdk">
+<Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
     <TargetFramework>net10.0</TargetFramework>
@@ -6,4 +6,8 @@
     <Nullable>enable</Nullable>
   </PropertyGroup>
 
+  <ItemGroup>
+    <PackageReference Include="Microsoft.Extensions.Identity.Stores" Version="10.0.7" />
+  </ItemGroup>
+
 </Project>