docs(api): document session sharing contract

[ysyneu]

Summary

• sync the public session get/list schemas with fc-safari access capability and share-state fields
• document the optional session get share token
• keep Safari split and consolidated OpenAPI specs identical

Verification

• parsed all four OpenAPI JSON files
• verified split/consolidated Safari contract parity
• confirmed service-only share endpoints remain excluded from app_key public APIs
• ran mint broken-links with Node 22.12.0