feat(ui/quiz): implement real-time global chapter quiz generation, submit results to database, and display dynamic statistics on dashboard

src/NexusReader.Application/Abstractions/Services/IIdentityService.cs

@@ -11,4 +11,5 @@ public interface IIdentityService
     Task<Result> LogoutAsync();
     Task<Result<UserProfileDto>> GetProfileAsync();
     Task<Result> RefreshTokenAsync();
+    void ClearCache();
 }

src/NexusReader.Application/Commands/Quiz/SubmitQuizResultCommand.cs

@@ -0,0 +1,10 @@
+using FluentResults;
+using NexusReader.Application.Abstractions.Messaging;
+
+namespace NexusReader.Application.Commands.Quiz;
+
+public record SubmitQuizResultCommand(
+    string UserId,
+    string Topic,
+    int Score,
+    int TotalQuestions) : ICommand;

src/NexusReader.Application/Commands/Quiz/SubmitQuizResultCommandHandler.cs

@@ -0,0 +1,44 @@
+using FluentResults;
+using Microsoft.EntityFrameworkCore;
+using NexusReader.Application.Abstractions.Messaging;
+using NexusReader.Data.Persistence;
+using NexusReader.Domain.Entities;
+
+namespace NexusReader.Application.Commands.Quiz;
+
+public sealed class SubmitQuizResultCommandHandler : ICommandHandler<SubmitQuizResultCommand>
+{
+    private readonly IDbContextFactory<AppDbContext> _dbContextFactory;
+
+    public SubmitQuizResultCommandHandler(IDbContextFactory<AppDbContext> dbContextFactory)
+    {
+        _dbContextFactory = dbContextFactory;
+    }
+
+    public async Task<Result> Handle(SubmitQuizResultCommand request, CancellationToken cancellationToken)
+    {
+        using var context = await _dbContextFactory.CreateDbContextAsync(cancellationToken);
+
+        var user = await context.Users.FirstOrDefaultAsync(u => u.Id == request.UserId, cancellationToken);
+        if (user == null)
+        {
+            return Result.Fail("User not found.");
+        }
+
+        var quizResult = new QuizResult
+        {
+            Id = Guid.NewGuid(),
+            UserId = request.UserId,
+            TenantId = string.IsNullOrEmpty(user.TenantId) ? "global" : user.TenantId,
+            Topic = request.Topic,
+            Score = request.Score,
+            TotalQuestions = request.TotalQuestions,
+            CompletedDate = DateTime.UtcNow
+        };
+
+        context.QuizResults.Add(quizResult);
+        await context.SaveChangesAsync(cancellationToken);
+
+        return Result.Ok();
+    }
+}

src/NexusReader.Application/DTOs/User/UserProfileDto.cs

@@ -5,6 +5,7 @@ namespace NexusReader.Application.DTOs.User;
 public record UserProfileDto
 {
     public string Email { get; init; } = string.Empty;
+    public string UserId { get; init; } = string.Empty;
     public int AITokensUsed { get; init; }
     public Guid TenantId { get; init; }
     
@@ -15,11 +16,11 @@ public record UserProfileDto
 
     public int AverageQuizScore { get; init; }
     
-    /// <summary>
-    /// Summary of the last read book.
-    /// </summary>
+    public string? DisplayName { get; init; }
+    public int BooksReadCount { get; init; }
+    public int ConceptsMappedCount { get; init; }
     public LastReadBookDto? LastReadBook { get; init; }
-
+    public IReadOnlyList<QuizResultDto> RecentQuizzes { get; init; } = Array.Empty<QuizResultDto>();
     public string[] Roles { get; init; } = Array.Empty<string>();
 
     // Helper properties for UI compatibility
@@ -40,3 +41,13 @@ public record LastReadBookDto
     public string? Description { get; init; }
     public bool IsReadyForReading { get; init; }
 }
+
+public record QuizResultDto
+{
+    public Guid Id { get; init; }
+    public string Topic { get; init; } = string.Empty;
+    public int Score { get; init; }
+    public int TotalQuestions { get; init; }
+    public double Percentage { get; init; }
+    public DateTime CompletedDate { get; init; }
+}

src/NexusReader.Application/Queries/Graph/GraphViewModels.cs

@@ -1,3 +1,4 @@
+using System.Collections.Generic;
 using System.Text.Json.Serialization;
 
 namespace NexusReader.Application.Queries.Graph;
@@ -7,7 +8,9 @@ public record GraphNodeDto(
     [property: JsonPropertyName("label")] string Label,
     [property: JsonPropertyName("group")] string Group,
     [property: JsonPropertyName("description")] string? Description = null,
-    [property: JsonPropertyName("type")] string? Type = null
+    [property: JsonPropertyName("type")] string? Type = null,
+    [property: JsonPropertyName("summary")] string? Summary = null,
+    [property: JsonPropertyName("key_terms")] List<string>? KeyTerms = null
 );
 
 public record GraphLinkDto(

src/NexusReader.Application/Queries/User/GetUserProfileQueryHandler.cs

@@ -23,6 +23,7 @@ public class GetUserProfileQueryHandler : IRequestHandler<GetUserProfileQuery, R
             .Select(u => new UserProfileDto
             {
                 Email = u.Email ?? string.Empty,
+                UserId = u.Id,
                 AITokensUsed = u.AITokensUsed,
                 TenantId = u.TenantId != null && u.TenantId.Length == 36 ? new Guid(u.TenantId) : Guid.Empty,
                 Plan = u.SubscriptionPlan != null ? new SubscriptionPlanDto
@@ -35,6 +36,9 @@ public class GetUserProfileQueryHandler : IRequestHandler<GetUserProfileQuery, R
                 AverageQuizScore = u.QuizResults.Any(q => q.TotalQuestions > 0) 
                     ? (int)u.QuizResults.Where(q => q.TotalQuestions > 0).Average(q => (double)q.Score / q.TotalQuestions * 100) 
                     : 0,
+                DisplayName = u.DisplayName,
+                BooksReadCount = u.Ebooks.Count(),
+                ConceptsMappedCount = dbContext.KnowledgeUnits.Count(k => k.TenantId == u.TenantId),
                 LastReadBook = u.Ebooks.OrderByDescending(e => e.LastReadDate).Select(e => new LastReadBookDto
                 {
                     Id = e.Id,
@@ -51,6 +55,15 @@ public class GetUserProfileQueryHandler : IRequestHandler<GetUserProfileQuery, R
                     Description = e.Description,
                     IsReadyForReading = e.IsReadyForReading
                 }).FirstOrDefault(),
+                RecentQuizzes = u.QuizResults.OrderByDescending(q => q.CompletedDate).Take(5).Select(q => new QuizResultDto
+                {
+                    Id = q.Id,
+                    Topic = q.Topic,
+                    Score = q.Score,
+                    TotalQuestions = q.TotalQuestions,
+                    Percentage = q.Percentage,
+                    CompletedDate = q.CompletedDate
+                }).ToList(),
                 Roles = dbContext.UserRoles
                     .Where(ur => ur.UserId == u.Id)
                     .Join(dbContext.Roles, ur => ur.RoleId, r => r.Id, (ur, r) => r.Name!)