feat: implement Neo4j knowledge graph synchronization and integrate global cache support with custom tenant claims.

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

@@ -38,7 +38,7 @@ public class GetUserProfileQueryHandler : IRequestHandler<GetUserProfileQuery, R
                     : 0,
                 DisplayName = u.DisplayName,
                 BooksReadCount = u.Ebooks.Count(),
-                ConceptsMappedCount = dbContext.KnowledgeUnits.Count(k => k.TenantId == u.TenantId),
+                ConceptsMappedCount = dbContext.KnowledgeUnits.Count(k => k.TenantId == u.TenantId || k.TenantId == "global" || string.IsNullOrEmpty(k.TenantId)),
                 LastReadBook = u.Ebooks.OrderByDescending(e => e.LastReadDate).Select(e => new LastReadBookDto
                 {
                     Id = e.Id,
@@ -64,6 +64,17 @@ public class GetUserProfileQueryHandler : IRequestHandler<GetUserProfileQuery, R
                     Percentage = q.Percentage,
                     CompletedDate = q.CompletedDate
                 }).ToList(),
+                MappedConcepts = dbContext.KnowledgeUnits
+                    .Where(k => k.TenantId == u.TenantId || k.TenantId == "global" || string.IsNullOrEmpty(k.TenantId))
+                    .OrderByDescending(k => k.CreatedAt)
+                    .Take(6)
+                    .Select(k => new MappedConceptDto
+                    {
+                        Id = k.Id,
+                        Type = k.Type.ToString(),
+                        Content = k.Content
+                    })
+                    .ToList(),
                 Roles = dbContext.UserRoles
                     .Where(ur => ur.UserId == u.Id)
                     .Join(dbContext.Roles, ur => ur.RoleId, r => r.Id, (ur, r) => r.Name!)