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/Chapter.cs

@@ -2,7 +2,7 @@ using Microsoft.EntityFrameworkCore;
 using Microsoft.EntityFrameworkCore.Metadata.Builders;
 using Novelly.Api.Beats;
 using Novelly.Api.Common;
-using Novelly.Api.Projects;
+using Novelly.Api.Novels;
 using Novelly.Api.Tags;
 
 namespace Novelly.Api.Chapters;
@@ -10,8 +10,8 @@ namespace Novelly.Api.Chapters;
 public class Chapter
 {
     public Guid Id { get; set; } = Guid.NewGuid();
-    public Guid ProjectId { get; set; }
-    public Project? Project { get; set; }
+    public Guid NovelId { get; set; }
+    public Novel? Novel { get; set; }
 
     public int Number { get; set; }
 
@@ -43,6 +43,6 @@ public class ChapterEntityTypeConfiguration : IEntityTypeConfiguration<Chapter>
     {
         entity.Property(c => c.Title).IsRequired().HasMaxLength(300);
         entity.Property(c => c.Status).HasConversion<string>().HasMaxLength(32);
-        entity.HasIndex(c => new { c.ProjectId, c.Number });
+        entity.HasIndex(c => new { c.NovelId, c.Number });
     }
 }