[CLAUDE] PurchaseEvaluation: D2 multi-winner outward — create-contract 1→N per winner + list-card winner names

Completes the Mig 58 multi-winner (>=2 cung trung) wiring — the audit's joint-winner
dead-ends, CEO-approved scope ("1 HD per winner"):
- create-contract 1->N: one draft HD per IsWinner supplier (was 409 dead-end for >=2).
  Command -> List<Guid>. ContractCodeGenerator self-commits its sequence per call, so
  gen all N codes first (contracts built local) then atomic add + single final
  SaveChanges (no partial create on failure). GiaTri: single = details ThanhTienNganSach
  sum (legacy preserved); >=2 = per-winner quote total (DangSoanThao draft, editable —
  anh Kiet UAT the basis). pe.ContractId = first (idempotency). Controller -> {contractIds}.
- list-card winner names: PurchaseEvaluationListItemDto +WinnerSupplierNames (EF
  collection subquery over IsWinner suppliers; translates + runs on SQLite — test-verified).
  FE PeListPanel shows joined names for >=2 (was blank). Dialog -> contractIds[] + "Da tao N HD".

Tests 413 -> 419 (+6: multi-contract 5 [per-winner GiaTri 140/260 vs single legacy 800,
idempotency, 0-winner, not-DaDuyet] + EF-subquery translation smoke). Full suite GREEN.
FE 2-app SHA-identical. reviewer PASS (codegen-sequencing, positional-record arg-order,
no-partial-create all independently verified).

UAT (anh Kiet): open a >=2-winner phieu -> "Tao HD" creates N draft contracts (1/winner);
confirm per-winner contract GiaTri (quote total) is the wanted basis.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/Backend/SolutionErp.Api/Controllers/PurchaseEvaluationsController.cs

@@ -294,9 +294,9 @@ public class PurchaseEvaluationsController(IMediator mediator) : ControllerBase
     public async Task<ActionResult<object>> CreateContractFromEvaluation(
         Guid id, [FromBody] CreateContractFromEvaluationBody body, CancellationToken ct)
     {
-        var contractId = await mediator.Send(new CreateContractFromEvaluationCommand(
+        var contractIds = await mediator.Send(new CreateContractFromEvaluationCommand(
             id, body.ContractType, body.TenHopDong, body.BypassProcurementAndCCM), ct);
-        return Ok(new { contractId });
+        return Ok(new { contractIds });   // [Mig 58 multi-winner] 1 HĐ / NCC trúng → list ids
     }
 
     // ========== Ý kiến 4 phòng ban ==========