Retrieves the state-bound values from the client's state_store and removes
the entry to enforce single-use semantics.
Arguments
- client
OAuthClient instance
- state
Plain (decrypted) state string used as the logical key
- shiny_session
Optional pre-captured Shiny session context (from
capture_shiny_session_context()) to include in audit events. Used when calling from async workers that lack access to the reactive domain.