Persistenz: SQLite + Dapper, chains/messages Tabellen, History-Endpoint, Frontend History-Load

Models/MessageRecord.cs

@@ -0,0 +1,15 @@
+namespace Gott.Models;
+
+public class MessageRecord
+{
+    public long Id { get; set; }
+    public string ChainId { get; set; }
+    public string Role { get; set; }         // user, assistant
+    public string Type { get; set; }         // text, tool_use, tool_result
+    public string Content { get; set; }      // Text oder JSON
+    public string ToolName { get; set; }     // null bei text
+    public string ToolCallId { get; set; }   // tool_use id
+    public bool IsError { get; set; }
+    public int Iteration { get; set; }       // welche Loop-Iteration
+    public string CreatedAt { get; set; }
+}