docs: sync gt-sanity 3.1.4 behavior - #443

Summary

• correct gt-sanity automatic import, reference patching, publishing, and draft defaults
• document persisted workflow preferences, explicit status states, and safe reference patching
• add the new locale-grouped Studio structure helpers and Debug info workflow
• update the v3.1 release note for the shipped persistence behavior

Verification

• installed and imported gt-sanity@3.1.4 in a clean npm project
• type-checked a clean Sanity config using all five workflow options plus gtStructure and gtStructureItems
• passed the 216-test gt-sanity suite and package typecheck after building workspace dependencies
• passed content validator tests, typecheck, structure/reference/callout/unsafe-HTML/link validation
• passed the 460-page production docs build