Story-3128 · functions lane

Suggest Drive only while it remains undiscovered

Counsel who have imported a document but never used Google Drive can now receive the import_from_drive onboarding ask. The ask is absent before the first document and retires as soon as any Drive-origin document exists.

The live predicate

has_document AND NOT has_drive_document

A historical document with a null intake origin does not count as a Drive import. Its firm remains eligible because the system never observed which door that document entered through.

One-query registry extension

The existing eligibility query adds one EXISTS projection for intake_origin = 'drive'. The code registry adds one ordered entry after add_first_document; dismissal, backoff, and suppression continue through the shared path with no special case.

Scope boundary

This change adds no Drive connection, OAuth storage, app copy, model call, manual trace span, service mechanism, dismissal mechanism, or schema change. Existing API and database auto-instrumentation remain the observability floor.