feat(approvals): label pending-approver chips with their group (objectui#2807) (#2811)

The drawer's 'waiting on' chips now key their collapse by (name, group) using
the framework's pending_approver_groups: the same person filling two groups
stays two labeled chips (Dev Admin · finance / · legal), one group filled
twice collapses to a single chip with a count. Group renders as a muted
· <group> sub-tag. Degrades to plain dedupe + count when no group data present.

Rebased onto latest main (resolves overlap with the #2810 admin-override
change in the same file).

Closes objectui#2807 (UI half)


Claude-Session: https://claude.ai/code/session_01Cu48mLFUdRBmMh8Z8R3CVz

Co-authored-by: Claude <noreply@anthropic.com>

Author: os-zhuang