Add genre feature; extract ConfirmModal for reusable confirm dialogs

Genres seed on boot, are editable per project, and gate agent config
errors more gracefully. ConfirmModal replaces ad-hoc confirm prompts
across chapters, tags, and characters pages.

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.Genres;
 using Novelly.Api.Imports;
 using Novelly.Api.Projects;
 using Novelly.Api.Questions;
@@ -86,6 +87,7 @@ app.MapProjectEndpoints()
    .MapChapterEndpoints()
    .MapBeatEndpoints()
    .MapTagEndpoints()
+   .MapGenreEndpoints()
    .MapOpenQuestionEndpoints()
    .MapAgentEndpoints()
    .MapImportEndpoints();