Improved Workspace assistant

Keep fresh Workspace assistant requests independent

Selected routing uses the current request first and consults bounded prior context only for unresolved follow-ups.

When capability selection is enabled, the Workspace assistant first selects from the current instruction and trusted saved-result kinds. It consults a bounded recent user-message envelope only when that route remains compact discovery and the request is a confirmation or referential follow-up. Self-contained requests therefore do not inherit tools from an earlier domain merely because they contain words such as “both” or “again”.