reminder_service.go: BuildDigest audience predicate switches the
"project lead anywhere on the path" branch from `pt.role = 'lead'` to
`pt.responsibility = 'lead'`. Two SQL sites + comment updated.
deadline_service.go: assertCanAdminProject (Reopen permission) switches
from `pt.role IN ('admin','lead')` to `pt.responsibility = 'lead'`.
The legacy 'admin' was already dead since t-paliad-051 — never present
in project_teams.role to begin with — so this also drops a slow leak.
Doc comments + error message updated.
derivation_service.go: ListDescendantStaffed SELECTs both `pt.role` and
`pt.responsibility`, returns the new column to the team-tab "from
descendants" subsection (so the firm-tier badge + responsibility pill
both render). ORDER BY switches to responsibility.
Build + vet clean. Pure-Go tests pass.
9184e9b0ef