The `policy`, `policy-mapping` and `group-info` receive paths applied every
incoming item unconditionally, so a delayed older grant (wide policy body,
old mapping, old group add) overwrote a newer revoke on the peer. `iam-user`
and `service-account` already compared the item's `updatedAt` with the local
record.
Route the three paths through one pure verdict helper: an item older than
the local record is acknowledged without being applied; items without a
source timestamp and items targeting an absent record keep today's behaviour
(older peers, idempotent deletes from backlog#2071). Deletes are gated the
same way so an older delete cannot remove a newer record.
The group record's own timestamp now moves on every membership and status
change instead of staying at creation, so the gate judges group items
against the last change. Add the IamSys accessors the gate reads
(`get_policy_doc`, `get_mapped_policy_record`, `get_group_info`).
(cherry picked from commit 98c32093406cb47014b7eda2fe139f01079de337)
唐小鸭
68499b6549