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/Imports/ImportContracts.cs

@@ -0,0 +1,78 @@
+using Novelly.Api.Common.Validation;
+
+namespace Novelly.Api.Imports;
+
+public record ImportJobResponse(
+    Guid Id,
+    string SourceRoot,
+    Guid? ProjectId,
+    ImportJobStatus Status,
+    string? StatusMessage,
+    int ChaptersCompleted,
+    int ChaptersTotal,
+    DateTimeOffset CreatedAt,
+    DateTimeOffset UpdatedAt);
+
+/// <summary>Whether a source folder is ready for a fresh import, has one to resume, or is already done.</summary>
+public enum ImportReadiness
+{
+    Fresh,
+    Resumable,
+    Complete
+}
+
+public record ImportInspectionResponse(
+    ImportReadiness Readiness,
+    Guid? ProjectId,
+    int ChaptersCompleted,
+    int ChaptersTotal,
+    IReadOnlyList<string> CompletedPasses);
+
+public record InspectImportRequest(string SourceRoot);
+
+public class InspectImportRequestValidator : IModelValidator<InspectImportRequest>
+{
+    public ValidationResult Validate(InspectImportRequest model)
+    {
+        var result = new ValidationResult();
+
+        if (string.IsNullOrWhiteSpace(model.SourceRoot))
+            result.AddError("SourceRoot", "'Source Root' must not be empty.");
+
+        return result;
+    }
+}
+
+/// <summary>
+/// Starts a fresh import, resumes an incomplete one, or — with <see cref="ForceRestart"/> —
+/// deletes the ledger and the project it points at before starting clean. Resuming needs no
+/// flag: the importer always continues from the ledger it finds unless told to wipe it.
+/// </summary>
+public record StartImportRequest(string SourceRoot, bool ForceRestart = false);
+
+public class StartImportRequestValidator : IModelValidator<StartImportRequest>
+{
+    public ValidationResult Validate(StartImportRequest model)
+    {
+        var result = new ValidationResult();
+
+        if (string.IsNullOrWhiteSpace(model.SourceRoot))
+            result.AddError("SourceRoot", "'Source Root' must not be empty.");
+
+        return result;
+    }
+}
+
+public static class ImportMapping
+{
+    public static ImportJobResponse ToResponse(this ImportJob job) => new(
+        job.Id,
+        job.SourceRoot,
+        job.ProjectId,
+        job.Status,
+        job.StatusMessage,
+        job.ChaptersCompleted,
+        job.ChaptersTotal,
+        job.CreatedAt,
+        job.UpdatedAt);
+}