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/LoggingTests.cs

@@ -7,10 +7,6 @@ using Novelly.Api.Projects;
 
 namespace Novelly.Api.Tests;
 
-/// <summary>
-/// Covers the logging behaviour added across the services: a warning fires before a
-/// not-found is thrown, and prose bodies never leak into a log message.
-/// </summary>
 [TestFixture]
 public class LoggingTests : ServiceTestFixture
 {
@@ -82,7 +78,7 @@ public class LoggingTests : ServiceTestFixture
         BeatLogs.Entries.Clear();
 
         Assert.That(
-            () => Beats.CreateAsync(chapter.Id, new CreateBeatRequest("Arrival", CharacterId: foreignCharacter.Id)),
+            () => Beats.CreateAsync(chapter.Id, new CreateBeatRequest("Arrival", CharacterIds: [foreignCharacter.Id])),
             Throws.TypeOf<InvalidOperationException>());
 
         Assert.Multiple(() =>