feat: support EU site

[Moran-k]

Add Multi-Region Support for EU Komodor Site

Summary

Adds support for the EU Komodor site while maintaining the US site as default. Users can now specify their region via a new --region flag.

Changes

Core Implementation

• pkg/portforward/ws.go: Added ResolveWebSocketURL() function with priority-based URL resolution
• pkg/portforward/ctl.go: Added Region field to Controller and threaded through calls
• pkg/portforward/cmd.go: Added --region CLI flag with validation and examples

Testing

• pkg/portforward/ws_test.go (new): Tests for URL resolution logic
  • Region aliases (us, eu) with case-insensitivity
  • Custom WebSocket URLs
  • Environment variable precedence
  • All 12 test cases passing

Documentation

• README.md: Updated with region usage examples and configuration details

Usage

# Default (US region)
komocli port-forward pod/mypod 5000 --namespace default --cluster my-cluster --token=...

# EU region
komocli port-forward pod/mypod 5000 --namespace default --cluster my-cluster --token=... --region eu