Add Kotlin LSP plugin for code intelligence

- Add kotlin-lsp entry to marketplace.json with support for .kt and .kts files
- Create README with installation instructions (brew install kotlin-lsp)
- Configure LSP server to use --stdio mode with 120s startup timeout

.claude-plugin/marketplace.json

@@ -167,6 +167,29 @@
         }
       }
     },
+    {
+      "name": "kotlin-lsp",
+      "description": "Kotlin language server for code intelligence",
+      "version": "1.0.0",
+      "author": {
+        "name": "Anthropic",
+        "email": "support@anthropic.com"
+      },
+      "source": "./plugins/kotlin-lsp",
+      "category": "development",
+      "strict": false,
+      "lspServers": {
+        "kotlin-lsp": {
+          "command": "kotlin-lsp",
+          "args": ["--stdio"],
+          "extensionToLanguage": {
+            ".kt": "kotlin",
+            ".kts": "kotlin"
+          },
+          "startupTimeout" : 120000
+        }
+      }
+    },
     {
       "name": "csharp-lsp",
       "description": "C# language server for code intelligence",