fix: Update API documentation links and remove unnecessary file types from docfx configuration

docs/api/index.md

@@ -4,14 +4,14 @@ Browse the generated API documentation for each EchoHub project.
 
 ## Projects
 
-### [Client](client/EchoHub.Client.yml)
+### Client
 
 Terminal.Gui v2 TUI application -- UI components, services, themes, and configuration.
 
-### [Core](core/EchoHub.Core.Constants.yml)
+### Core
 
 Shared library -- DTOs, models, constants, and the SignalR client contract.
 
-### [Server](server/EchoHub.Server.Controllers.yml)
+### Server
 
 ASP.NET Core server -- controllers, hubs, authentication, and data access.

docs/docfx.json

@@ -41,19 +41,19 @@
       {
         "src": "_api_meta/core",
         "dest": "api/core",
-        "files": ["*.yml", ".manifest"],
+        "files": ["*.yml"],
         "exclude": ["toc.yml"]
       },
       {
         "src": "_api_meta/server",
         "dest": "api/server",
-        "files": ["*.yml", ".manifest"],
+        "files": ["*.yml"],
         "exclude": ["toc.yml"]
       },
       {
         "src": "_api_meta/client",
         "dest": "api/client",
-        "files": ["*.yml", ".manifest"],
+        "files": ["*.yml"],
         "exclude": ["toc.yml"]
       }
     ],