feat(numbering): projects get their own dedicated number sequence (decoupled from orders)

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

src/__tests__/numbering.test.ts

@@ -6,6 +6,9 @@ import {
   isSharedNumberTaken,
   previewOfferNumber,
   isOfferNumberTaken,
+  generateProjectNumber,
+  previewProjectNumber,
+  isProjectNumberTaken,
 } from "../services/numbering.service";
 import prisma from "../config/database";
 
@@ -77,6 +80,38 @@ describe("generateSharedNumber", () => {
   });
 });
 
+describe("generateProjectNumber", () => {
+  beforeEach(async () => {
+    await prisma.number_sequences.deleteMany({ where: { type: "project" } });
+  });
+
+  afterEach(async () => {
+    await prisma.number_sequences.deleteMany({ where: { type: "project" } });
+  });
+
+  it("returns a non-empty string", async () => {
+    const num = await generateProjectNumber();
+    expect(typeof num).toBe("string");
+    expect(num.length).toBeGreaterThan(0);
+  });
+
+  it("increments the sequence by exactly 1 and preserves the year/format", async () => {
+    // Seed high so neither generated number collides with a real project →
+    // the skip-taken retry never fires and the increment is strictly +1.
+    await seedSequence("project", 900000);
+    const num1 = await generateProjectNumber();
+    const num2 = await generateProjectNumber();
+    assertStrictIncrement(num1, num2);
+  });
+
+  it("previewProjectNumber returns a number not yet taken by a project", async () => {
+    const preview = await previewProjectNumber();
+    expect(typeof preview).toBe("string");
+    expect(preview.length).toBeGreaterThan(0);
+    expect(await isProjectNumberTaken(preview)).toBe(false);
+  });
+});
+
 describe("generateOfferNumber", () => {
   beforeEach(async () => {
     await prisma.number_sequences.deleteMany({ where: { type: "offer" } });