E1.3.3 Merge once approved #34

Part of: Land PR #20 and document the global --allow-t3 (E1.3).

Task

Merge once approved

Subtasks

• Confirm checks green
• Do not release in the same step

Definition of done

• Tests added or updated and CI green
• Docs updated when the command surface or output changes
• No private registry data, local paths or private repository names in fixtures or docs