v4.1.0

### Added

- **Workspace Management**: Global workspace cache to track active hub instances across different working directories
  - New `/api/workspaces` endpoint to list all active workspace instances
  - Real-time workspace updates via new `workspaces_updated` SSE subscription event
  - XDG-compliant workspace cache storage (`~/.local/state/mcp-hub/workspaces.json`)
  - Automatic cleanup of stale workspace entries

- **Multi-Configuration File Support**: Enhanced configuration system with intelligent merging
  - CLI now accepts multiple `--config` arguments: `--config global.json --config project.json`
  - Later configuration files override earlier ones with smart merging rules
  - Missing configuration files are gracefully skipped
  - Enhanced file watching for all specified configuration files

- **Global Environment Variable Injection**: `MCP_HUB_ENV` environment variable support
  - Parse JSON string from `MCP_HUB_ENV` and inject key-value pairs into all MCP server environments
  - Useful for passing shared secrets, tokens, or configuration to all servers
  - Server-specific `env` fields always override global values

### Enhanced

- **Health Endpoint**: Now includes comprehensive workspace information showing current workspace and all active instances
- **Configuration Management**: Enhanced ConfigManager with robust array-based config path handling
- **File Watching**: Improved configuration file monitoring across multiple files with better change detection
- **Error Handling**: Enhanced error handling and logging throughout the workspace management system
- Updated all dependencies to latest versions for improved security and performance