E3.2.1 Add --strict (and a family setting) for family-ink #58

Part of: Icon QA lets weak or off-brand icons pass (E3.2).

Task

Add --strict (and a family setting) for family-ink

Subtasks

• Default unchanged
• Document in references/content.md

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