Add outline import feature; drop Dto naming, map entities at the API boundary

Services now return entities; endpoints (and the agent toolsets) map to
*Response records instead of services building wire DTOs themselves.
Also brings in the outline-import agent, MCP tool, ledger and web dialog
that were already in progress on disk.

src/Novelly.Api/Program.cs

@@ -7,6 +7,7 @@ using Novelly.Api.Chapters;
 using Novelly.Api.Characters;
 using Novelly.Api.Common;
 using Novelly.Api.Data;
+using Novelly.Api.Imports;
 using Novelly.Api.Projects;
 using Novelly.Api.Questions;
 using Novelly.Api.Scenes;
@@ -98,7 +99,8 @@ app.MapProjectEndpoints()
    .MapSceneEndpoints()
    .MapTagEndpoints()
    .MapOpenQuestionEndpoints()
-   .MapAgentEndpoints();
+   .MapAgentEndpoints()
+   .MapImportEndpoints();
 
 app.Run();