fix: migrate from deprecated io/ioutil and enhance Workbench compatib…

[kjw3]

…ility tests

Major Changes:

• Replace io/ioutil with io and os packages across 10 files (14 function calls)
  • ioutil.ReadAll -> io.ReadAll
  • ioutil.ReadFile -> os.ReadFile
  • ioutil.WriteFile -> os.WriteFile
  • ioutil.ReadDir -> os.ReadDir
• Remove duplicate start command registration in pkg/cmd/cmd.go

Workbench Compatibility Enhancements:

• Add comprehensive documentation to cli_output_compatibility_test.go
• Add Test_ListWithOrgFlag to verify 'brev ls --org' support
• Add Test_ShortHelpFlag to verify 'brev -h' works (Workbench uses this)
• Add Test_VersionWithNoCheckLatestFlag for flag variation testing
• Add Test_InstanceListColumnHeadersStability for critical column validation
• Add Test_OrgListColumnHeadersStability for org list format
• Add Test_CommandExistenceForWorkbench for comprehensive command checks
• Improve Test_StartCommandFormat to explicitly verify --org flag

All changes verified with successful build and test execution. Tests ensure backward compatibility with NVIDIA AI Workbench integration.

[Copilot]

Pull Request Overview

This PR modernizes the codebase by migrating from the deprecated io/ioutil package to the standard io and os packages, removes a duplicate command registration, and adds comprehensive Workbench compatibility tests with detailed documentation.

• Replaces all io/ioutil function calls with their modern equivalents (io.ReadAll, os.ReadFile, os.WriteFile, os.ReadDir)
• Removes duplicate start command registration in command tree initialization
• Adds 7 new integration tests with extensive documentation of NVIDIA AI Workbench dependencies

Reviewed Changes

Copilot reviewed 13 out of 13 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
pkg/workspacemanagerv2/containermanager_test.go	Replace ioutil.ReadDir with os.ReadDir
pkg/store/workspace.go	Replace ioutil.ReadAll with io.ReadAll
pkg/store/file.go	Replace ioutil.ReadAll with io.ReadAll
pkg/store/authtoken.go	Replace ioutil.ReadAll with io.ReadAll
pkg/setupworkspace/setupworkspace.go	Replace ioutil.ReadFile and ioutil.WriteFile with os equivalents
pkg/mergeshells/mergeshells.go	Replace ioutil.ReadAll and ioutil.ReadDir with modern equivalents
pkg/integration/cli_output_compatibility_test.go	Add comprehensive Workbench compatibility tests and documentation
pkg/huproxyclient/huproxyclient.go	Replace ioutil.ReadAll with io.ReadAll
pkg/files/files.go	Replace ioutil.ReadAll and ioutil.WriteFile with modern equivalents
pkg/cmd/paths/paths.go	Replace ioutil.ReadDir with os.ReadDir
pkg/cmd/importideconfig/importideconfig.go	Replace ioutil.ReadDir with os.ReadDir
pkg/cmd/cmd.go	Remove duplicate start.NewCmdStart command registration
pkg/cmd/clipboard/clipboard_listener.go	Replace ioutil.ReadAll with io.ReadAll

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[Copilot]

Pull Request Overview

Copilot reviewed 13 out of 13 changed files in this pull request and generated no new comments.

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