feat(documents): persist & expose selected_custom_fields in services

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

src/__tests__/selected-custom-fields.test.ts

@@ -3,6 +3,9 @@ import {
   encodeSelectedCustomFields,
   parseSelectedCustomFields,
 } from "../utils/custom-fields";
+import { afterAll } from "vitest";
+import { createOffer, getOffer } from "../services/offers.service";
+import prisma from "../config/database";
 
 describe("selected custom fields encode/decode", () => {
   it("encodes a non-empty index array to a JSON string", () => {
@@ -36,3 +39,35 @@ describe("selected custom fields encode/decode", () => {
     ]);
   });
 });
+
+describe("offers selected_custom_fields round-trip", () => {
+  const created: number[] = [];
+  afterAll(async () => {
+    if (created.length)
+      await prisma.quotations.deleteMany({ where: { id: { in: created } } });
+  });
+
+  it("persists selection on create and decodes it on detail", async () => {
+    const res = (await createOffer({
+      status: "draft",
+      selected_custom_fields: [2, 0, 0],
+    })) as { id: number };
+    created.push(res.id);
+
+    const row = await prisma.quotations.findUnique({ where: { id: res.id } });
+    expect(row?.selected_custom_fields).toBe("[0,2]");
+
+    const detail = await getOffer(res.id);
+    expect(detail?.selected_custom_fields).toEqual([0, 2]);
+  });
+
+  it("stores null when selection is empty", async () => {
+    const res = (await createOffer({
+      status: "draft",
+      selected_custom_fields: [],
+    })) as { id: number };
+    created.push(res.id);
+    const row = await prisma.quotations.findUnique({ where: { id: res.id } });
+    expect(row?.selected_custom_fields).toBeNull();
+  });
+});