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/OpenQuestionTests.cs

@@ -88,7 +88,6 @@ public class OpenQuestionTests : ServiceTestFixture
             Assert.That(open.Select(q => q.Question), Is.EqualTo(new[] { "Is this one book or two?" }));
             Assert.That(everything, Has.Count.EqualTo(2));
 
-            // Still-open questions come first, so the list stays about what is undecided.
             Assert.That(everything[0].IsResolved, Is.False);
             Assert.That(everything[1].IsResolved, Is.True);
         });
@@ -128,7 +127,6 @@ public class OpenQuestionTests : ServiceTestFixture
 
         Assert.Multiple(() =>
         {
-            // The existing note is kept and the decision lands underneath it.
             Assert.That(chapter.Notes, Does.StartWith("Runs long."));
             Assert.That(chapter.Notes, Does.Contain("Where does the chapter break? — After the harbour burns."));
             Assert.That(character.Notes, Is.EqualTo("Where does the chapter break? — After the harbour burns."));
@@ -179,7 +177,6 @@ public class OpenQuestionTests : ServiceTestFixture
         {
             Assert.That(detached.ChapterId, Is.Null);
 
-            // Only the chapter was cleared — a null id means "leave alone", not "detach".
             Assert.That(detached.CharacterId, Is.EqualTo(_characterId));
         });
     }