feat(qualification-criteria): dnd reordering with whole-list PATCH

The chevron up/down buttons rewrote a single row's display_order,
which didn't actually swap positions since the neighbouring rows kept
their original orders. Replaced with a proper drag-handle (dnd-kit
sortable, matching the waiting-list-manager pattern) backed by a new
POST /admin/qualification-criteria/reorder endpoint that rewrites
display_order = index for every row in a transaction. The service
rejects partial / extraneous id lists so a stale UI can't silently
drop a criterion. Optimistic local-cache update keeps the row in
position during the round-trip; rollback on error.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/lib/services/qualification.service.ts

@@ -14,10 +14,11 @@ import { and, asc, eq } from 'drizzle-orm';
 import { db } from '@/lib/db';
 import { interestQualifications, interests, qualificationCriteria } from '@/lib/db/schema';
 import { createAuditLog, type AuditMeta } from '@/lib/audit';
-import { ConflictError, NotFoundError } from '@/lib/errors';
+import { ConflictError, NotFoundError, ValidationError } from '@/lib/errors';
 import { emitToRoom } from '@/lib/socket/server';
 import type {
   CreateQualificationCriterionInput,
+  ReorderQualificationCriteriaInput,
   SetInterestQualificationInput,
   UpdateQualificationCriterionInput,
 } from '@/lib/validators/qualification';
@@ -137,6 +138,70 @@ export async function deleteCriterion(id: string, portId: string, meta: AuditMet
   return { ok: true };
 }
 
+/**
+ * Whole-list reorder. Rewrites display_order to match the array index of
+ * each id, inside a single transaction so partial failure can't leave the
+ * port with a scrambled order. The ids array must cover exactly the port's
+ * current criteria — any mismatch (extra or missing id) is rejected so the
+ * UI can't silently drop a criterion by sending a stale list.
+ */
+export async function reorderCriteria(
+  portId: string,
+  data: ReorderQualificationCriteriaInput,
+  meta: AuditMeta,
+) {
+  return db
+    .transaction(async (tx) => {
+      const current = await tx
+        .select({ id: qualificationCriteria.id })
+        .from(qualificationCriteria)
+        .where(eq(qualificationCriteria.portId, portId));
+
+      const currentIds = new Set(current.map((r) => r.id));
+      const incomingIds = new Set(data.ids);
+
+      if (
+        currentIds.size !== incomingIds.size ||
+        [...currentIds].some((id) => !incomingIds.has(id))
+      ) {
+        throw new ValidationError(
+          'Reorder payload must reference exactly the port’s current criteria',
+        );
+      }
+
+      for (let i = 0; i < data.ids.length; i++) {
+        await tx
+          .update(qualificationCriteria)
+          .set({ displayOrder: i, updatedAt: new Date() })
+          .where(
+            and(
+              eq(qualificationCriteria.id, data.ids[i]!),
+              eq(qualificationCriteria.portId, portId),
+            ),
+          );
+      }
+
+      return tx
+        .select()
+        .from(qualificationCriteria)
+        .where(eq(qualificationCriteria.portId, portId))
+        .orderBy(asc(qualificationCriteria.displayOrder), asc(qualificationCriteria.createdAt));
+    })
+    .then((rows) => {
+      void createAuditLog({
+        userId: meta.userId,
+        portId,
+        action: 'update',
+        entityType: 'qualification_criterion',
+        entityId: 'reorder',
+        newValue: { orderedIds: data.ids },
+        ipAddress: meta.ipAddress,
+        userAgent: meta.userAgent,
+      });
+      return rows;
+    });
+}
+
 // ─── Per-interest state ─────────────────────────────────────────────────────
 
 export interface QualificationRow {

src/lib/validators/qualification.ts

@@ -22,6 +22,15 @@ export const updateQualificationCriterionSchema = createQualificationCriterionSc
   .omit({ key: true })
   .partial();
 
+/**
+ * Whole-list reorder. The IDs array must cover exactly the port's current
+ * criteria — the service rejects partial / extraneous IDs to keep the
+ * resulting display_order contiguous.
+ */
+export const reorderQualificationCriteriaSchema = z.object({
+  ids: z.array(z.string().min(1)).min(1),
+});
+
 /**
  * Per-interest qualification state. Only `confirmed` + optional `notes` are
  * writable — `confirmedAt` / `confirmedBy` are stamped server-side from
@@ -36,3 +45,4 @@ export const setInterestQualificationSchema = z.object({
 export type CreateQualificationCriterionInput = z.infer<typeof createQualificationCriterionSchema>;
 export type UpdateQualificationCriterionInput = z.infer<typeof updateQualificationCriterionSchema>;
 export type SetInterestQualificationInput = z.infer<typeof setInterestQualificationSchema>;
+export type ReorderQualificationCriteriaInput = z.infer<typeof reorderQualificationCriteriaSchema>;