Add environment flag to rad resource list command

[Copilot]

Description

Adds -e/--environment flag to rad resource list to filter resources by environment, similar to the existing -a/--application filter.

Changes:

• Add --environment/-e flag to filter resources by environment name
• Validate mutual exclusivity between --application and --environment flags
• Add unit tests for environment filtering and error handling

Usage:

rad resource list Applications.Core/containers -e my-env
rad resource list Applications.Core/containers --environment production

Type of change

• This pull request adds or changes features of Radius and has an approved issue (issue link required).

Fixes: #8192

Contributor checklist

Please verify that the PR meets the following requirements, where applicable:

• An overview of proposed schema changes is included in a linked GitHub issue.
  • Yes
  • Not applicable
• A design document PR is created in the design-notes repository, if new APIs are being introduced.
  • Yes
  • Not applicable
• The design document has been reviewed and approved by Radius maintainers/approvers.
  • Yes
  • Not applicable
• A PR for the samples repository is created, if existing samples are affected by the changes in this PR.
  • Yes
  • Not applicable
• A PR for the documentation repository is created, if the changes in this PR affect the documentation or any user facing updates are made.
  • Yes
  • Not applicable
• A PR for the recipes repository is created, if existing recipes are affected by the changes in this PR.
  • Yes
  • Not applicable

Original prompt

---

This section details on the original issue you should resolve

<issue_title>List all resources in a given environment with rad resource list</issue_title>
<issue_description>### Overview of feature request

Right now, we don't have rad resource list -e default. I think that it could be nice to have a command that would list all the resources within a given environment .

Maybe a list that looks like the following might be helpful:
NAME - RESOURCE TYPE - STATUS

Acceptance criteria

• Have a command rad resource list that lists all the resources in the default environment.
• It can also accept an environment flag: rad resource list -e not-default-env

Additional context

kubectl get all -n <namespace>

Code -https://github.com/radius-project/radius/blob/main/pkg/cli/cmd/resource/list/list.go

Would you like to support us?

• Yes, I would like to support you

AB#12953</issue_description>

<agent_instructions>follow all coding standards for the Radius project and repository</agent_instructions>

Comments on the Issue (you are @copilot in this section)

@ytimocin That command does not support environment level resources. Not sure if we want to do that. Feel free to close if that is not a priority. cc/ @Reshrahim

• Fixes List all resources in a given environment with rad resource list #7789

---

💡 You can make Copilot smarter by setting up custom instructions, customizing its development environment and configuring Model Context Protocol (MCP) servers. Learn more Copilot coding agent tips in the docs.