Add character aliases/identity links, move-beats, keyboard help overlay

- Characters can carry aliases and be linked as the same underlying
  person (canonical SameCharacterAsId, optional reveal chapter/note),
  surfaced through the API, MCP tools, agent toolset, and web UI.
- Characters page redesigned as a filterable/sortable table (name+
  aliases, role, importance, occupation, tags) instead of a sidebar
  list, to stay usable as the cast grows.
- Beats can be moved between chapters (BeatService.MoveAsync + MCP/
  agent tool + endpoint).
- Add a keyboard-shortcuts help overlay (HelpButton/HelpOverlayContext)
  wired into the project layout.
- CLAUDE.md: require every frontend component to carry a unique id
  attribute; apply it to CharacterMultiSelect and MarkdownEditor.

src/Novelly.Mcp/NovelApiClient.cs

@@ -27,6 +27,12 @@ public class NovelApiClient(HttpClient http, ILogger<NovelApiClient> logger)
             Content = JsonContent.Create(body, options: Options)
         }, ct);
 
+    public Task<CallToolResult> PutAsync(string path, object body, CancellationToken ct = default) =>
+        SendAsync(new HttpRequestMessage(HttpMethod.Put, path)
+        {
+            Content = JsonContent.Create(body, options: Options)
+        }, ct);
+
     public Task<CallToolResult> DeleteAsync(string path, CancellationToken ct = default) => SendAsync(new HttpRequestMessage(HttpMethod.Delete, path), ct);
 
     private async Task<CallToolResult> SendAsync(HttpRequestMessage request, CancellationToken ct)