Enabled sending document analysis sessions with attachments in the chat (#627)

Co-authored-by: Thorsten Sommer <mail@tsommer.org>

app/MindWork AI Studio/Assistants/DocumentAnalysis/DocumentAnalysisAssistant.razor.cs

@@ -118,10 +118,47 @@ public partial class DocumentAnalysisAssistant : AssistantBaseCore<SettingsDialo
 
     protected override bool SubmitDisabled => (this.IsNoPolicySelected || this.loadedDocumentPaths.Count==0);
 
-    protected override ChatThread ConvertToChatThread => (this.chatThread ?? new()) with
+    protected override ChatThread ConvertToChatThread
     {
-        SystemPrompt = SystemPrompts.DEFAULT,
-    };
+        get
+        {
+            if (this.chatThread is null || this.chatThread.Blocks.Count < 2)
+            {
+                return new ChatThread
+                {
+                    SystemPrompt = SystemPrompts.DEFAULT
+                };
+            }
+
+            return new ChatThread
+            {
+                ChatId = Guid.NewGuid(),
+                Name = string.Format(T("{0} - Document Analysis Session"), this.selectedPolicy?.PolicyName ?? T("Empty")),
+                SystemPrompt = SystemPrompts.DEFAULT,
+                Blocks =
+                [
+                    // Replace the first "user block" (here, it was/is the block generated by the assistant) with a new one
+                    // that includes the loaded document paths and a standard message about the previous analysis session:
+                    new ContentBlock
+                    {
+                        Time = this.chatThread.Blocks.First().Time,
+                        Role = ChatRole.USER,
+                        HideFromUser = false,
+                        ContentType = ContentType.TEXT,
+                        Content = new ContentText
+                        {
+                            Text = this.T("The result of your previous document analysis session."),
+                            FileAttachments = this.loadedDocumentPaths.ToList(),
+                        }
+                    },
+                    
+                    // Then, append the last block of the current chat thread
+                    // (which is expected to be the AI response):
+                    this.chatThread.Blocks.Last(),
+                ]
+            };
+        }
+    }
 
     protected override void ResetForm()
     {