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/.

tests/Novelly.Api.Tests/TestDatabase.cs

@@ -4,16 +4,6 @@ using Novelly.Api.Data;
 
 namespace Novelly.Api.Tests;
 
-/// <summary>
-/// A throwaway SQLite database held in memory. Using real SQLite rather than the
-/// in-memory provider means the tests exercise the same relational behaviour the app
-/// ships with — cascade deletes, foreign keys and all.
-/// </summary>
-/// <remarks>
-/// NUnit reuses one fixture instance across every test in a class, so this must be built
-/// in <c>[SetUp]</c> and disposed in <c>[TearDown]</c>. A field initialiser would share
-/// one database for the whole class and let tests see each other's rows.
-/// </remarks>
 public class TestDatabase : IDisposable
 {
     private readonly SqliteConnection _connection;
@@ -29,7 +19,6 @@ public class TestDatabase : IDisposable
 
     public NovelDbContext Context { get; }
 
-    /// <summary>A second context over the same database, for asserting on persisted state.</summary>
     public NovelDbContext CreateContext() =>
         new(new DbContextOptionsBuilder<NovelDbContext>().UseSqlite(_connection).Options);