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

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

@@ -21,6 +21,7 @@ public record UserProfileDto
     public int ConceptsMappedCount { get; init; }
     public LastReadBookDto? LastReadBook { get; init; }
     public IReadOnlyList<QuizResultDto> RecentQuizzes { get; init; } = Array.Empty<QuizResultDto>();
+    public IReadOnlyList<MappedConceptDto> MappedConcepts { get; init; } = Array.Empty<MappedConceptDto>();
     public string[] Roles { get; init; } = Array.Empty<string>();
 
     // Helper properties for UI compatibility
@@ -29,6 +30,14 @@ public record UserProfileDto
     public string LastReadBookTitle => LastReadBook?.Title ?? PlanConstants.DefaultActivityLabel;
 }
 
+public record MappedConceptDto
+{
+    public string Id { get; init; } = string.Empty;
+    public string Type { get; init; } = string.Empty;
+    public string Content { get; init; } = string.Empty;
+    public string DisplayLabel => Content.Length > 25 ? Content.Substring(0, 22) + "..." : Content;
+}
+
 public record LastReadBookDto
 {
     public Guid Id { get; init; }

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!)

src/NexusReader.Infrastructure/Services/KnowledgeService.cs

@@ -90,7 +90,7 @@ public class KnowledgeService : IKnowledgeService
 
         // 1. Check Cache
         var cached = await dbContext.SemanticKnowledgeCache
-            .FirstOrDefaultAsync(c => c.ContentHash == hash && c.TenantId == tenantId, cancellationToken);
+            .FirstOrDefaultAsync(c => c.ContentHash == hash && (c.TenantId == tenantId || c.TenantId == "global"), cancellationToken);
         
         if (cached != null && cached.PromptVersion == PromptVersion)
         {
@@ -98,7 +98,12 @@ public class KnowledgeService : IKnowledgeService
             try
             {
                 var packet = JsonSerializer.Deserialize<KnowledgePacket>(cached.JsonData, JsonOptions);
-                if (packet != null) return Result.Ok(packet);
+                if (packet != null)
+                {
+                    await ProcessKnowledgeUnitsAsync(packet, tenantId, ebookId, dbContext, cancellationToken);
+                    await dbContext.SaveChangesAsync(cancellationToken);
+                    return Result.Ok(packet);
+                }
             }
             catch (JsonException ex)
             {
@@ -226,6 +231,30 @@ public class KnowledgeService : IKnowledgeService
 
     private async Task ProcessKnowledgeUnitsAsync(KnowledgePacket packet, string tenantId, Guid? ebookId, AppDbContext dbContext, CancellationToken cancellationToken)
     {
+        if (packet.Graph != null && (packet.Units == null || !packet.Units.Any()))
+        {
+            var graphUnits = packet.Graph.Nodes.Select(node => new KnowledgeUnitDto(
+                node.Id,
+                node.Type ?? "concept",
+                node.Description ?? node.Label,
+                new Dictionary<string, object>
+                {
+                    ["label"] = node.Label,
+                    ["group"] = node.Group,
+                    ["summary"] = node.Summary ?? "",
+                    ["key_terms"] = node.KeyTerms ?? new List<string>()
+                }
+            )).ToList();
+
+            var graphLinks = packet.Graph.Links.Select(link => new KnowledgeLinkDto(
+                link.Source,
+                link.Target,
+                link.RelationType
+            )).ToList();
+
+            packet = packet with { Units = graphUnits, Links = graphLinks };
+        }
+
         var unitIds = packet.Units.Select(u => u.Id).ToList();
         var linkSourceIds = packet.Links.Select(l => l.Source).ToList();
         var linkTargetIds = packet.Links.Select(l => l.Target).ToList();
@@ -341,6 +370,79 @@ public class KnowledgeService : IKnowledgeService
                 _logger.LogError(ex, "[KnowledgeService] Failed to generate and upsert embeddings for knowledge units to Qdrant.");
             }
         }
+
+        // 6. Synchronize to Neo4j graph database
+        await SyncToNeo4jAsync(packet, cancellationToken);
+    }
+
+    private async Task SyncToNeo4jAsync(KnowledgePacket packet, CancellationToken cancellationToken)
+    {
+        if (packet.Units == null || !packet.Units.Any()) return;
+
+        try
+        {
+            await using var session = _neo4jDriver.AsyncSession();
+
+            // 1. Merge nodes in a transaction
+            await session.ExecuteWriteAsync(async tx =>
+            {
+                foreach (var unit in packet.Units)
+                {
+                    var cypher = @"
+                        MERGE (u:KnowledgeUnit {id: $id})
+                        ON CREATE SET u.content = $content, u.type = $type
+                        ON MATCH SET u.content = $content, u.type = $type";
+                    
+                    var guidStr = GetDeterministicGuid(unit.Id).ToString();
+                    await tx.RunAsync(cypher, new 
+                    { 
+                        id = guidStr, 
+                        content = unit.Content ?? string.Empty, 
+                        type = unit.Type ?? "concept" 
+                    });
+                }
+            });
+
+            // 2. Merge links in a transaction
+            if (packet.Links != null && packet.Links.Any())
+            {
+                await session.ExecuteWriteAsync(async tx =>
+                {
+                    foreach (var link in packet.Links)
+                    {
+                        if (string.IsNullOrWhiteSpace(link.Source) || string.IsNullOrWhiteSpace(link.Target))
+                            continue;
+
+                        var relationType = string.IsNullOrWhiteSpace(link.Relation) ? "RELATED_TO" : link.Relation.Trim().ToUpperInvariant();
+                        relationType = System.Text.RegularExpressions.Regex.Replace(relationType, @"[^A-Z0-9_]", "_");
+                        if (string.IsNullOrEmpty(relationType) || relationType == "_")
+                        {
+                            relationType = "RELATED_TO";
+                        }
+
+                        var cypher = $@"
+                            MATCH (source:KnowledgeUnit {{id: $sourceId}})
+                            MATCH (target:KnowledgeUnit {{id: $targetId}})
+                            MERGE (source)-[r:{relationType}]->(target)";
+
+                        var sourceGuidStr = GetDeterministicGuid(link.Source).ToString();
+                        var targetGuidStr = GetDeterministicGuid(link.Target).ToString();
+
+                        await tx.RunAsync(cypher, new 
+                        { 
+                            sourceId = sourceGuidStr, 
+                            targetId = targetGuidStr 
+                        });
+                    }
+                });
+            }
+
+            _logger.LogInformation("[KnowledgeService] Successfully synchronized {NodeCount} nodes and {LinkCount} links to Neo4j.", packet.Units.Count, packet.Links?.Count ?? 0);
+        }
+        catch (Exception ex)
+        {
+            _logger.LogError(ex, "[KnowledgeService] Failed to synchronize knowledge graph to Neo4j.");
+        }
     }
 
     private async Task EnsureCollectionExistsAsync(string collectionName, CancellationToken cancellationToken = default)
@@ -381,6 +483,14 @@ public class KnowledgeService : IKnowledgeService
         return new Guid(hash);
     }
 
+    private static string GetPointIdString(PointId pointId)
+    {
+        if (pointId == null) return string.Empty;
+        return pointId.PointIdOptionsCase == PointId.PointIdOptionsOneofCase.Uuid
+            ? pointId.Uuid
+            : pointId.Num.ToString();
+    }
+
     public async Task<Result<GroundednessResult>> VerifyGroundednessAsync(string answer, string context, string tenantId, CancellationToken cancellationToken = default)
     {
         var systemPrompt = @"
@@ -463,10 +573,28 @@ public class KnowledgeService : IKnowledgeService
                 searchResult = new List<Qdrant.Client.Grpc.ScoredPoint>();
             }
 
-            var contexts = searchResult.Select(point => new RelevantContext 
+            var contexts = searchResult.Select(point => 
             { 
-                Text = point.Payload.TryGetValue("content", out var cv) ? cv.StringValue : string.Empty, 
+                var content = point.Payload.TryGetValue("content", out var cv) ? cv.StringValue : string.Empty;
-                Confidence = point.Score 
+                var summary = string.Empty;
+                if (point.Payload.TryGetValue("metadataJson", out var metaVal) && !string.IsNullOrEmpty(metaVal.StringValue))
+                {
+                    try
+                    {
+                        var meta = JsonSerializer.Deserialize<Dictionary<string, object>>(metaVal.StringValue);
+                        if (meta != null && meta.TryGetValue("summary", out var sumObj))
+                        {
+                            summary = sumObj?.ToString();
+                        }
+                    }
+                    catch {}
+                }
+                var text = string.IsNullOrEmpty(summary) ? content : $"{content}: {summary}";
+                return new RelevantContext 
+                { 
+                    Text = text, 
+                    Confidence = point.Score 
+                };
             }).ToList();
 
             return Result.Ok(contexts);
@@ -534,7 +662,7 @@ public class KnowledgeService : IKnowledgeService
             }
 
             // 3. Graph Expansion via Neo4j
-            var candidateIds = searchResult.Select(r => r.Id.ToString()).ToList();
+            var candidateIds = searchResult.Select(r => GetPointIdString(r.Id)).ToList();
             var definitions = new Dictionary<string, List<string>>();
 
             if (candidateIds.Any())
@@ -543,7 +671,7 @@ public class KnowledgeService : IKnowledgeService
                 {
                     await using var session = _neo4jDriver.AsyncSession();
                     var cypher = @"
-                        MATCH (source:KnowledgeUnit)-[r:DEFINES]->(target:KnowledgeUnit)
+                        MATCH (source:KnowledgeUnit)-[r]->(target:KnowledgeUnit)
                         WHERE source.id IN $candidateIds
                         RETURN source.id AS sourceId, target.content AS targetContent";
                     
@@ -617,7 +745,7 @@ public class KnowledgeService : IKnowledgeService
 
                 var dto = new SemanticSearchResultDto
                 {
-                    ContentHash = point.Id.ToString(),
+                    ContentHash = GetPointIdString(point.Id),
                     Snippet = content,
                     UnitType = type,
                     RelevanceScore = point.Score,
@@ -625,7 +753,7 @@ public class KnowledgeService : IKnowledgeService
                     Metadata = metadata
                 };
 
-                var pointIdStr = point.Id.ToString();
+                var pointIdStr = GetPointIdString(point.Id);
                 if (definitions.TryGetValue(pointIdStr, out var pointDefs) && pointDefs.Any())
                 {
                     dto.Snippet = $"[Context: {string.Join("; ", pointDefs)}]\n{dto.Snippet}";
@@ -724,11 +852,26 @@ public class KnowledgeService : IKnowledgeService
             }
 
             // 3. Graph Expansion via Neo4j
-            var candidateIds = searchResult.Select(r => r.Id.ToString()).ToList();
+            var candidateIds = searchResult.Select(r => GetPointIdString(r.Id)).ToList();
             var relatedContexts = new List<string>();
             
             // Keep map of point ID -> payload data for fast mapping later
-            var pointMap = searchResult.ToDictionary(r => r.Id.ToString(), r => r);
+            var pointMap = searchResult.ToDictionary(r => GetPointIdString(r.Id), r => r);
+
+            // Fetch knowledge units from PostgreSQL to map Guids back to rich metadata summaries
+            var guidMap = new Dictionary<string, KnowledgeUnit>();
+            try
+            {
+                using var dbContext = await _dbContextFactory.CreateDbContextAsync(cancellationToken);
+                var units = await dbContext.KnowledgeUnits
+                    .Where(u => u.TenantId == tenantId && (ebookId == null || u.EbookId == ebookId))
+                    .ToListAsync(cancellationToken);
+                guidMap = units.ToDictionary(u => GetDeterministicGuid(u.Id).ToString(), u => u);
+            }
+            catch (Exception ex)
+            {
+                _logger.LogWarning(ex, "[KnowledgeService] Failed to load KnowledgeUnits from PostgreSQL for Guid mapping.");
+            }
 
             if (candidateIds.Any())
             {
@@ -738,7 +881,7 @@ public class KnowledgeService : IKnowledgeService
                     var cypher = @"
                         MATCH (source:KnowledgeUnit)
                         WHERE source.id IN $candidateIds
-                        OPTIONAL MATCH (source)-[r:DEFINES|RELATED_TO]->(target:KnowledgeUnit)
+                        OPTIONAL MATCH (source)-[r]->(target:KnowledgeUnit)
                         RETURN source.id AS sourceId, source.content AS sourceContent,
                                collect({ targetId: target.id, targetContent: target.content, relation: type(r) }) AS relations";
                     
@@ -751,23 +894,64 @@ public class KnowledgeService : IKnowledgeService
                     foreach (var record in neoResult)
                     {
                         var sourceId = record["sourceId"].As<string>();
-                        var sourceContent = record["sourceContent"].As<string>();
                         
-                        relatedContexts.Add($"[Source ID: {sourceId}] {sourceContent}");
+                        var sourceText = string.Empty;
+                        if (guidMap.TryGetValue(sourceId, out var sourceUnit))
+                        {
+                            var summary = string.Empty;
+                            if (!string.IsNullOrEmpty(sourceUnit.MetadataJson))
+                            {
+                                try
+                                {
+                                    var meta = JsonSerializer.Deserialize<Dictionary<string, object>>(sourceUnit.MetadataJson);
+                                    if (meta != null && meta.TryGetValue("summary", out var sumObj))
+                                    {
+                                        summary = sumObj?.ToString();
+                                    }
+                                }
+                                catch { }
+                            }
+                            sourceText = string.IsNullOrEmpty(summary) ? sourceUnit.Content : $"{sourceUnit.Content}: {summary}";
+                        }
+                        else
+                        {
+                            sourceText = record["sourceContent"].As<string>();
+                        }
+                        
+                        relatedContexts.Add($"[Source ID: {sourceId}] {sourceText}");
                         
                         var relations = record["relations"].As<List<object>>();
                         if (relations != null)
                         {
                             foreach (var relObj in relations)
                             {
-                                if (relObj is Dictionary<string, object> relDict &&
+                                if (relObj is System.Collections.IDictionary relDict)
-                                    relDict.TryGetValue("targetId", out var targetIdVal) && targetIdVal is string targetId &&
-                                    relDict.TryGetValue("targetContent", out var targetContentVal) && targetContentVal is string targetContent &&
-                                    relDict.TryGetValue("relation", out var relationVal) && relationVal is string relation)
                                 {
-                                    if (!string.IsNullOrEmpty(targetContent))
+                                    var targetId = relDict["targetId"]?.ToString();
+                                    var targetContent = relDict["targetContent"]?.ToString();
+                                    var relation = relDict["relation"]?.ToString();
+
+                                    if (!string.IsNullOrEmpty(targetContent) && !string.IsNullOrEmpty(relation))
                                     {
-                                        relatedContexts.Add($"[Related Context ({relation}) to {sourceId}] {targetContent}");
+                                        var targetText = targetContent;
+                                        if (!string.IsNullOrEmpty(targetId) && guidMap.TryGetValue(targetId, out var targetUnit))
+                                        {
+                                            var summary = string.Empty;
+                                            if (!string.IsNullOrEmpty(targetUnit.MetadataJson))
+                                            {
+                                                try
+                                                {
+                                                    var meta = JsonSerializer.Deserialize<Dictionary<string, object>>(targetUnit.MetadataJson);
+                                                    if (meta != null && meta.TryGetValue("summary", out var sumObj))
+                                                    {
+                                                        summary = sumObj?.ToString();
+                                                    }
+                                                }
+                                                catch { }
+                                            }
+                                            targetText = string.IsNullOrEmpty(summary) ? targetUnit.Content : $"{targetUnit.Content}: {summary}";
+                                        }
+                                        relatedContexts.Add($"[Related Context ({relation}) to {sourceId}] {targetText}");
                                     }
                                 }
                             }
@@ -779,9 +963,32 @@ public class KnowledgeService : IKnowledgeService
                     _logger.LogWarning(ex, "[KnowledgeService] Neo4j graph expansion failed. Falling back to direct Qdrant points.");
                     foreach (var point in searchResult)
                     {
-                        var sourceId = point.Id.ToString();
+                        var sourceId = GetPointIdString(point.Id);
-                        var content = point.Payload.TryGetValue("content", out var cv) ? cv.StringValue : string.Empty;
+                        
-                        relatedContexts.Add($"[Source ID: {sourceId}] {content}");
+                        var sourceText = string.Empty;
+                        if (guidMap.TryGetValue(sourceId, out var sourceUnit))
+                        {
+                            var summary = string.Empty;
+                            if (!string.IsNullOrEmpty(sourceUnit.MetadataJson))
+                            {
+                                try
+                                {
+                                    var meta = JsonSerializer.Deserialize<Dictionary<string, object>>(sourceUnit.MetadataJson);
+                                    if (meta != null && meta.TryGetValue("summary", out var sumObj))
+                                    {
+                                        summary = sumObj?.ToString();
+                                    }
+                                }
+                                catch { }
+                            }
+                            sourceText = string.IsNullOrEmpty(summary) ? sourceUnit.Content : $"{sourceUnit.Content}: {summary}";
+                        }
+                        else
+                        {
+                            sourceText = point.Payload.TryGetValue("content", out var cv) ? cv.StringValue : string.Empty;
+                        }
+
+                        relatedContexts.Add($"[Source ID: {sourceId}] {sourceText}");
                     }
                 }
             }
@@ -805,33 +1012,14 @@ public class KnowledgeService : IKnowledgeService
             // 5. Build prompt and invoke Gemini with structured JSON formatting
             var contextBlocksText = string.Join("\n\n", relatedContexts);
 
-            var systemPrompt = @"
+            var systemPrompt = PromptRegistry.GroundedRAGSystemPrompt;
-You are an advanced, extremely precise Fact-Checking AI assistant. Your task is to answer the user's question using ONLY the provided context blocks.
-
-Strict Grounding Rules:
-1. Rely EXCLUSIVELY on the provided context. Do NOT use any pre-existing external knowledge, facts, or assumptions.
-2. If the context does not contain the answer, you must state exactly: 'I cannot answer this based on the provided book context.'
-3. For every statement or claim you make in your answer, you must cite the specific source IDs (e.g., source chunk ID or hash) from the context.
-4. You must format your response ONLY as a JSON object matching the following structure:
-{
-  ""answer"": ""The answer text goes here, referencing [Source ID] as citations."",
-  ""citations"": [
-    {
-      ""citationId"": ""The exact source ID cited (e.g., chunk hash/ID)"",
-      ""snippet"": ""The precise sentence or phrase from the context that supports this statement."",
-      ""sourceBook"": ""The book title or 'Unknown'""
-    }
-  ]
-}
-";
 
             var userPrompt = $"Context:\n{contextBlocksText}\n\nQuestion: {question}";
 
             var options = new ChatOptions
             {
                 Temperature = 0.0f,
-                MaxOutputTokens = 1500,
+                MaxOutputTokens = 1500
-                ResponseFormat = ChatResponseFormat.Json
             };
 
             var chatResponse = await _retryPipeline.ExecuteAsync(async ct => 
@@ -843,6 +1031,20 @@ Strict Grounding Rules:
 
             var rawJson = chatResponse.Text?.Trim() ?? string.Empty;
             rawJson = rawJson.Replace("```json", "").Replace("```", "").Trim();
+
+            // Handle direct text fallback when model bypasses JSON format
+            if (!rawJson.StartsWith("{") && 
+                (rawJson.Contains("cannot answer", StringComparison.OrdinalIgnoreCase) || 
+                 rawJson.Contains("context does not contain", StringComparison.OrdinalIgnoreCase) || 
+                 rawJson.Contains("provided book context", StringComparison.OrdinalIgnoreCase)))
+            {
+                return Result.Ok(new GroundedResponseDto
+                {
+                    Answer = "I cannot answer this based on the provided book context.",
+                    Citations = new List<CitationDto>()
+                });
+            }
+
             rawJson = JsonRepairHelper.Repair(rawJson);
 
             try
@@ -897,6 +1099,20 @@ Strict Grounding Rules:
                 _logger.LogWarning(ex, "[KnowledgeService] Failed to drop Qdrant collection 'knowledge_units' during cache clear.");
             }
 
+            try
+            {
+                await using var session = _neo4jDriver.AsyncSession();
+                await session.ExecuteWriteAsync(async tx =>
+                {
+                    await tx.RunAsync("MATCH (n:KnowledgeUnit) DETACH DELETE n");
+                });
+                _logger.LogInformation("[KnowledgeService] Successfully wiped Neo4j 'KnowledgeUnit' nodes.");
+            }
+            catch (Exception ex)
+            {
+                _logger.LogWarning(ex, "[KnowledgeService] Failed to wipe Neo4j graph during cache clear.");
+            }
+
             return Result.Ok();
         }
         catch (Exception ex)

src/NexusReader.Infrastructure/Services/PromptRegistry.cs

@@ -58,4 +58,24 @@ public static class PromptRegistry
         "\"units\": [ { \"id\": \"string\", \"type\": \"Section|Table|Definition|Rule\", \"content\": \"string\", \"metadata\": { \"page\": 0 } } ], " +
         "\"links\": [ { \"source\": \"string\", \"target\": \"string\", \"relation\": \"Next|Defines|Contains|References\" } ] " +
         "}.";
+
+    public const string GroundedRAGSystemPrompt = """
+        You are an advanced, extremely precise Fact-Checking AI assistant. Your task is to answer the user's question using ONLY the provided context blocks.
+
+        Strict Grounding Rules:
+        1. Rely EXCLUSIVELY on the provided context. Do NOT use any pre-existing external knowledge, facts, or assumptions.
+        2. If the context does not contain the answer, you must set the "answer" property in the JSON object exactly to: 'I cannot answer this based on the provided book context.' and the "citations" array must be empty.
+        3. For every statement or claim you make in your answer, you must cite the specific source IDs (e.g., source chunk ID or hash) from the context.
+        4. You must format your response ONLY as a JSON object matching the following structure:
+        {
+          "answer": "The answer text goes here, referencing [Source ID] as citations.",
+          "citations": [
+            {
+              "citationId": "The exact source ID cited (e.g., chunk hash/ID)",
+              "snippet": "The precise sentence or phrase from the context that supports this statement.",
+              "sourceBook": "The book title or 'Unknown'"
+            }
+          ]
+        }
+        """;
 }

src/NexusReader.UI.Shared/Pages/Dashboard.razor

@@ -5,6 +5,7 @@
 @using NexusReader.UI.Shared.Services
 @inject IIdentityService IdentityService
 @inject NavigationManager NavigationManager
+@inject ISyncService SyncService
 @attribute [Authorize]
 @implements IDisposable
 
@@ -55,12 +56,49 @@
                         <NexusIcon Name="arrow-right" Size="16" />
                     </div>
                     <div class="graph-placeholder">
-                        <div class="graph-node central"></div>
+                        <div class="graph-node central" title="Ośrodek Wiedzy Nexus Reader"></div>
-                        <div class="graph-node satellite" style="--angle: 0deg; --dist: 60px;"></div>
+                        
-                        <div class="graph-node satellite" style="--angle: 120deg; --dist: 50px;"></div>
+                        @if (_profile?.MappedConcepts != null && _profile.MappedConcepts.Any())
-                        <div class="graph-node satellite" style="--angle: 240deg; --dist: 70px;"></div>
+                        {
-                        <div class="active-node-label">TU JESTEŚ</div>
+                            @for (int i = 0; i < _profile.MappedConcepts.Count; i++)
+                            {
+                                var concept = _profile.MappedConcepts[i];
+                                var angle = i * (360.0 / _profile.MappedConcepts.Count);
+                                var dist = 65;
+                                <div class="graph-node satellite" 
+                                     style="--angle: @(angle)deg; --dist: @(dist)px;"
+                                     title="[@concept.Type] @concept.Content"
+                                     @onmouseover="() => SetHoveredConcept(concept)"
+                                     @onmouseout="ClearHoveredConcept">
+                                </div>
+                            }
+                        }
+                        else
+                        {
+                            <div class="graph-node satellite" style="--angle: 0deg; --dist: 60px;"></div>
+                            <div class="graph-node satellite" style="--angle: 120deg; --dist: 50px;"></div>
+                            <div class="graph-node satellite" style="--angle: 240deg; --dist: 70px;"></div>
+                        }
+                        
+                        <div class="active-node-label">
+                            @(string.IsNullOrEmpty(_hoveredConceptLabel) ? "TU JESTEŚ" : _hoveredConceptLabel)
+                        </div>
                     </div>
+                    
+                    @if (_hoveredConcept != null)
+                    {
+                        <div class="concept-detail-toast">
+                            <span class="concept-type">@_hoveredConcept.Type</span>
+                            <p class="concept-content">@_hoveredConcept.Content</p>
+                        </div>
+                    }
+                    else
+                    {
+                        <div class="concept-detail-toast placeholder">
+                            <span class="concept-type">Mapowanie AI</span>
+                            <p class="concept-content">Najedź na węzeł, aby zbadać pojęcie wydobyte przez Nexus AI.</p>
+                        </div>
+                    }
                 </section>
 
                 <!-- Quiz Summary -->
@@ -105,11 +143,28 @@
 
 @code {
     private UserProfileDto? _profile;
+    private MappedConceptDto? _hoveredConcept;
+    private string _hoveredConceptLabel = string.Empty;
 
     protected override async Task OnInitializedAsync()
     {
         IdentityService.OnStateInvalidated += HandleStateInvalidatedAsync;
         await LoadProfileAsync();
+        
+        await SyncService.InitializeAsync();
+        SyncService.OnProgressReceived += HandleProgressReceivedAsync;
+    }
+
+    private void SetHoveredConcept(MappedConceptDto concept)
+    {
+        _hoveredConcept = concept;
+        _hoveredConceptLabel = concept.DisplayLabel;
+    }
+
+    private void ClearHoveredConcept()
+    {
+        _hoveredConcept = null;
+        _hoveredConceptLabel = string.Empty;
     }
 
     private async Task LoadProfileAsync()
@@ -134,9 +189,19 @@
         });
     }
 
+    private async Task HandleProgressReceivedAsync(string pageId, DateTime timestamp)
+    {
+        await InvokeAsync(async () =>
+        {
+            IdentityService.ClearCache();
+            await LoadProfileAsync();
+        });
+    }
+
     public void Dispose()
     {
         IdentityService.OnStateInvalidated -= HandleStateInvalidatedAsync;
+        SyncService.OnProgressReceived -= HandleProgressReceivedAsync;
     }
 }
 

src/NexusReader.UI.Shared/Pages/Dashboard.razor.css

@@ -294,9 +294,19 @@
 }
 
 .graph-node.satellite {
-    width: 20px;
+    width: 16px;
-    height: 20px;
+    height: 16px;
     transform: rotate(var(--angle)) translateY(var(--dist));
+    background: rgba(0, 255, 153, 0.4);
+    border: 1px solid var(--nexus-neon);
+    cursor: pointer;
+    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
+}
+
+.graph-node.satellite:hover {
+    background: var(--nexus-neon);
+    box-shadow: 0 0 15px var(--nexus-neon);
+    transform: rotate(var(--angle)) translateY(var(--dist)) scale(1.3);
 }
 
 .active-node-label {
@@ -480,3 +490,41 @@
     color: #666666;
     margin-top: 0.5rem;
 }
+
+/* --- Concept Detail Toast for Dashboard --- */
+.concept-detail-toast {
+    margin-top: 1rem;
+    padding: 0.75rem 1rem;
+    background: rgba(255, 255, 255, 0.02);
+    border: 1px solid rgba(255, 255, 255, 0.05);
+    border-radius: 12px;
+    min-height: 80px;
+    display: flex;
+    flex-direction: column;
+    gap: 0.25rem;
+    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
+}
+
+.concept-detail-toast.placeholder {
+    opacity: 0.5;
+}
+
+.concept-type {
+    font-size: 0.75rem;
+    font-weight: 700;
+    color: var(--nexus-neon);
+    text-transform: uppercase;
+    letter-spacing: 1px;
+}
+
+.concept-content {
+    font-size: 0.85rem;
+    line-height: 1.4;
+    color: #E0E0E0;
+    margin: 0;
+    display: -webkit-box;
+    -webkit-line-clamp: 2;
+    -webkit-box-orient: vertical;
+    overflow: hidden;
+}
+

src/NexusReader.UI.Shared/Services/SyncService.cs

@@ -92,7 +92,7 @@ public class SyncService : ISyncService, IAsyncDisposable
 
                 if (_hubConnection?.State == HubConnectionState.Connected)
                 {
-                    await _hubConnection.SendAsync("UpdateProgress", pageId, ebookId, progress, chapterTitle, token);
+                    await _hubConnection.SendAsync("UpdateProgress", pageId, ebookId, progress, chapterTitle, chapterIndex);
                     _lastSentPageId = pageId;
                 }
             }

src/NexusReader.Web/Program.cs

@@ -106,7 +106,8 @@ builder.Services.AddAuthentication(options =>
 
 builder.Services.AddIdentityApiEndpoints<NexusUser>()
     .AddRoles<IdentityRole>()
-    .AddEntityFrameworkStores<AppDbContext>();
+    .AddEntityFrameworkStores<AppDbContext>()
+    .AddClaimsPrincipalFactory<NexusReader.Web.Services.CustomUserClaimsPrincipalFactory>();
 
 builder.Services.ConfigureApplicationCookie(options =>
 {

src/NexusReader.Web/Services/CustomUserClaimsPrincipalFactory.cs

@@ -0,0 +1,28 @@
+using System.Security.Claims;
+using System.Threading.Tasks;
+using Microsoft.AspNetCore.Identity;
+using Microsoft.Extensions.Options;
+using NexusReader.Domain.Entities;
+
+namespace NexusReader.Web.Services;
+
+public class CustomUserClaimsPrincipalFactory : UserClaimsPrincipalFactory<NexusUser, IdentityRole>
+{
+    public CustomUserClaimsPrincipalFactory(
+        UserManager<NexusUser> userManager,
+        RoleManager<IdentityRole> roleManager,
+        IOptions<IdentityOptions> optionsAccessor)
+        : base(userManager, roleManager, optionsAccessor)
+    {
+    }
+
+    protected override async Task<ClaimsIdentity> GenerateClaimsAsync(NexusUser user)
+    {
+        var identity = await base.GenerateClaimsAsync(user);
+        if (!string.IsNullOrEmpty(user.TenantId))
+        {
+            identity.AddClaim(new Claim("TenantId", user.TenantId));
+        }
+        return identity;
+    }
+}

tests/NexusReader.Application.Tests/Queries/CheckDatabaseTest.cs

@@ -0,0 +1,58 @@
+using System;
+using System.IO;
+using System.Text.Json;
+using System.Threading.Tasks;
+using Microsoft.EntityFrameworkCore;
+using NexusReader.Data.Persistence;
+using Xunit;
+
+namespace NexusReader.Application.Tests.Queries;
+
+public class CheckDatabaseTest
+{
+    [Fact]
+    public async Task PrintDatabaseStats()
+    {
+        var configJson = await File.ReadAllTextAsync("../../../../../src/NexusReader.Web/appsettings.json");
+        var doc = JsonDocument.Parse(configJson);
+        var pgConn = doc.RootElement.GetProperty("ConnectionStrings").GetProperty("PostgresConnection").GetString();
+        
+        Console.WriteLine($"Postgres Connection: {pgConn}");
+        
+        var optionsBuilder = new DbContextOptionsBuilder<AppDbContext>();
+        optionsBuilder.UseNpgsql(pgConn);
+        
+        using var context = new AppDbContext(optionsBuilder.Options);
+        
+        var usersCount = await context.Users.CountAsync();
+        var ebooksCount = await context.Ebooks.CountAsync();
+        var unitsCount = await context.KnowledgeUnits.CountAsync();
+        var cacheCount = await context.SemanticKnowledgeCache.CountAsync();
+        
+        Console.WriteLine($"=== DATABASE STATS ===");
+        Console.WriteLine($"Users: {usersCount}");
+        Console.WriteLine($"Ebooks: {ebooksCount}");
+        Console.WriteLine($"KnowledgeUnits: {unitsCount}");
+        Console.WriteLine($"SemanticKnowledgeCache: {cacheCount}");
+        
+        var users = await context.Users.ToListAsync();
+        foreach (var u in users)
+        {
+            Console.WriteLine($"User: {u.Email}, TenantId: '{u.TenantId}'");
+        }
+        
+        var ebooks = await context.Ebooks.ToListAsync();
+        foreach (var eb in ebooks)
+        {
+            Console.WriteLine($"Ebook Id: {eb.Id}, Title: '{eb.Title}', FilePath: '{eb.FilePath}', Ready: {eb.IsReadyForReading}");
+        }
+        
+        var cache = await context.SemanticKnowledgeCache.ToListAsync();
+        foreach (var c in cache)
+        {
+            Console.WriteLine($"Cache Hash: {c.ContentHash}, TenantId: '{c.TenantId}', PromptVersion: {c.PromptVersion}, JsonData Preview: {c.JsonData.Substring(0, Math.Min(c.JsonData.Length, 150))}");
+        }
+        
+        Assert.True(true);
+    }
+}