Remove Scenes, group beats by multiple characters; strip comments repo-wide

Drop the Scene entity/grouping in favor of chapters carrying prose directly
and beats belonging to many characters. Add markdown editor + character
multi-select components to the web client. Remove all XML doc and inline
comments across the touched C#/TS/CSS files in favor of self-documenting
names, and record that convention in CLAUDE.md. Add .mcp.json (local MCP
server config, no secrets) and ignore .idea/.

src/Novelly.Api/Projects/ProjectService.cs

@@ -27,12 +27,11 @@ public class ProjectService(
                 p.Phase,
                 p.Characters.Count,
                 p.Chapters.Count,
-                p.Chapters.SelectMany(c => c.Scenes).Sum(s => (int?)s.WordCount) ?? 0,
+                p.Chapters.Sum(c => (int?)c.WordCount) ?? 0,
                 p.UpdatedAt))
             .ToListAsync(ct);
     }
 
-    /// <summary>Null when no project has this id — a lookup miss is expected, not exceptional.</summary>
     public async Task<Project?> GetAsync(Guid id, CancellationToken ct = default)
     {
         Guard.Default(id, nameof(id));
@@ -92,7 +91,6 @@ public class ProjectService(
         return project;
     }
 
-    /// <summary>True if a project was deleted; false if no project had this id.</summary>
     public async Task<bool> DeleteAsync(Guid id, CancellationToken ct = default)
     {
         Guard.Default(id, nameof(id));