Rename Project concept to Novel across the stack

Renames the domain concept from Project to Novel throughout the backend
(entities, DTOs, services, endpoints, ProjectAccessService/Permission,
ProjectId foreign keys), MCP server (tool names and routes), and the
React/Vite frontend (types, hooks, routes, components). Adds a new EF
Core migration (RenameProjectToNovel) using RenameTable/RenameColumn to
preserve existing data instead of dropping/recreating tables. Updates
CLAUDE.md's structure section to reference Novels/ instead of Projects/.

src/Novelly.Api/Chapters/ChapterContracts.cs

@@ -7,7 +7,7 @@ namespace Novelly.Api.Chapters;
 
 public record ChapterSummaryResponse(
     Guid Id,
-    Guid ProjectId,
+    Guid NovelId,
     int Number,
     string Title,
     string? Summary,
@@ -21,7 +21,7 @@ public record ChapterSummaryResponse(
 
 public record ChapterResponse(
     Guid Id,
-    Guid ProjectId,
+    Guid NovelId,
     int Number,
     string Title,
     string? Summary,
@@ -115,7 +115,7 @@ file static class ChapterValidation
 public static class ChapterMapping
 {
     public static ChapterResponse ToResponse(this Chapter c) => new(
-        c.Id, c.ProjectId, c.Number, c.Title, c.Summary,
+        c.Id, c.NovelId, c.Number, c.Title, c.Summary,
         c.Setting, c.Notes,
         c.Status, c.TargetWordCount,
         [.. c.Beats.OrderBy(b => b.SortOrder).Select(b => b.ToResponse())],
@@ -124,7 +124,7 @@ public static class ChapterMapping
         c.UpdatedAt);
 
     public static ChapterSummaryResponse ToSummaryResponse(this Chapter c) => new(
-        c.Id, c.ProjectId, c.Number, c.Title, c.Summary,
+        c.Id, c.NovelId, c.Number, c.Title, c.Summary,
         c.Setting, c.Status, c.TargetWordCount,
         c.Beats.Count, c.WordCount,
         [.. c.Tags.OrderBy(t => t.Name).Select(t => t.ToResponse())],