feat(mcp): enhance MCP installation with status tracking and custom configs

- Add /mcp-servers/ to .gitignore for MCP server installations
- Extend mcp_installations table with status, logs, and validation fields
- Refactor MCP install route to support custom configs, enable logs, and async installation
- Improve MCPSyncService with promise-based syncing to prevent concurrent operations

This update improves MCP management by adding robust installation tracking, custom configuration support, and better error handling for a more reliable user experience.

database/schema.sql

@@ -34,6 +34,12 @@ CREATE TABLE IF NOT EXISTS mcp_installations (
   name TEXT NOT NULL,
   config JSON NOT NULL,
   tools JSON,
+  status TEXT DEFAULT 'pending',
+  status_message TEXT,
+  environment_path TEXT,
+  executable_command TEXT,
+  validation_result TEXT,
+  install_logs TEXT,
   installed_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
   updated_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP
 );