feat: support selecting multiple namespaces for resource views, close #261

[smoothzz]

Summary

Adds support for selecting multiple namespaces in resource views, allowing users to filter resources across multiple namespaces simultaneously.

Changes

• Updated NamespaceSelector to support multi-select mode with checkboxes
• Added search functionality to filter namespaces
• Updated ResourceTable to handle array of namespaces instead of single namespace
• Implemented client-side filtering when multiple namespaces are selected
• Shows namespace badges for selected namespaces
• Maintains backward compatibility with single-select mode (for dialogs)
• Updated localStorage to store array of namespaces

Testing

Tested locally with k3d cluster - multi-namespace selection works correctly with filtering and displays.

Closes #261

[zxh326]

This will default to requesting all namespaces