feat(web-admin): plan form package UI keyed by product and package spec

Contract-bound stop products use package options from the contract, arrange-qty
cache/API include packageSpec, and save validates required package selections.

Co-authored-by: Cursor <cursoragent@cursor.com>

web-admin/src/utils/pl-plan-stop-form.ts

@@ -6,6 +6,7 @@ import {
   isPlDibangOptionalVehiclePlate,
   isPlInternalCustomerName
 } from '@/utils/pl-internal-customer'
+import { normalizePackageSpec } from '@/utils/pl-plan-contract-product'
 
 export interface PlanStopProductFormRow {
   id?: string
@@ -214,6 +215,17 @@ function matchPrevStopProduct(
       return stopProducts[byPlanProductId]
     }
   }
+  const targetPkg = normalizePackageSpec(planRow.packageSpec)
+  const byProductAndPkg = stopProducts.findIndex(
+    (row, index) =>
+      !used.has(index) &&
+      String(row.productId) === String(planRow.productId) &&
+      normalizePackageSpec(row.packageSpec) === targetPkg
+  )
+  if (byProductAndPkg >= 0) {
+    used.add(byProductAndPkg)
+    return stopProducts[byProductAndPkg]
+  }
   const byProductId = stopProducts.findIndex(
     (row, index) => !used.has(index) && String(row.productId) === String(planRow.productId)
   )