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/.

CLAUDE.md

@@ -9,7 +9,7 @@ Novelly: software plan + write novel. ASP.NET Core 10, C#, TypeScript, React, .N
 ## Structure
 
 - `src/Novelly.Api/` — whole back end, organised by feature. One folder per feature holds
-  entity, DTOs, service, endpoints together: `Projects/`, `Characters/`, `Chapters/`, `Beats/`,
+  entity, DTOs, service, endpoints together: `Novels/`, `Characters/`, `Chapters/`, `Beats/`,
   `Scenes/`, `Tags/`, `Agent/`. `Common/` holds what crosses features; `Data/` holds
   `DbContext` + EF migrations.
 - `src/Novelly.AppHost/` — .NET Aspire orchestration; run this to bring up API + web client