feat(procurement): government tender cycle — committees, technical/financial gate, multi-vendor award

Adds the documented, auditable purchase cycle on top of the existing
PR/quote infrastructure: a tender booklet (كراسة شروط) per PR, vendor
invitations that open a quote record per vendor (rejected quotes stay
on file with their reason, never deleted), technical committee
evaluation with the 3-accepted-offer minimum before financial review
(otherwise the tender is flagged for re-tender with a reason), a
financial committee comparison scoped to technically-accepted quotes
only, and item-level award that can split one PR across several
vendors and therefore several purchase orders — replacing the old
strict PR:PO 1:1 assumption. Every PO produced carries its tender and
evaluation id back to the original PR.