CRAFT_PUBLISH_STATE_GITHUB_REPO identity override

Trap: using the workspace-resolved getGlobalGitHubConfig() for publish-state identity appears consistent, but a workspace may publish through a release repository different from the controller’s checkout repository. The controller then cannot locate Craft’s retry state. Fix: getPublishStateGitHubConfig() accepts only owner/repo from CRAFT_PUBLISH_STATE_GITHUB_REPO and applies it only to getPublishStatePath(); target construction and publishing retain the resolved workspace GitHub config. Reject malformed overrides with ConfigurationError. Chose a narrow state-key override over replacing global GitHub configuration because replacing it silently redirects publish behavior.