GitHub host support

Version 1 supports GitHub.com only.

The public -HostName parameter remains part of the command contract so GitHub Enterprise support can be added without redesigning the public API. For version 1, the supported value is github.com (case-insensitive).

All four public commands fail closed for any other hostname:

• Copy-GitHubRepository
• Get-GitHubRepository
• Start-CopyGitHubRepositoryWizard
• Test-GitHubRepositoryMigration

Unsupported hosts produce the structured GitHubHostNotSupported error before prerequisite checks, repository discovery, planning, verification, or remote mutation begin.

This fail-closed behavior prevents repository discovery through one GitHub host while a later operation implicitly targets another host. GitHub Enterprise Server and other GitHub hosts remain outside the version 1 product contract.

For the broader module-version, prerequisite, operating-system, compatibility, deprecation, and end-of-support rules, see Support, compatibility, and deprecation policy.