chore: update .gitignore

Co-Authored-By: Claude Sonnet 4.5 (1M context) <noreply@anthropic.com>

Author: sjnims

.gitignore

@@ -1,9 +1,6 @@
 # Claude Code plugin settings (user-specific configuration)
 .claude/*.local.md
 
-# MCP server configuration (user-specific)
-.mcp.json
-
 # Node modules (if any scripts use Node)
 node_modules/
 
@@ -26,6 +23,3 @@ __pycache__/
 # Environment variables
 .env
 .env.local
-
-# Serena
-.serena/