Enhance branch management with foreign key relation handling

- Updated `BranchesModule` to include foreign key relations in list and write responses, ensuring they are represented as nested objects using `pickRelation`.
- Introduced new `relation-response.mdc` file to define guidelines for embedding foreign key relations.
- Modified `BranchesRepository` to support fetching related `division`, `createdByUser`, and `updatedByUser` data.
- Updated DTOs and service methods to reflect changes in response structure, removing direct foreign key IDs.
- Added unit tests to validate the new relation handling in branches service and repository.
- Enhanced e2e tests to verify the correct structure of branch responses with nested relations.

test/branches.e2e-spec.ts

@@ -26,6 +26,8 @@ describe('Branches (e2e)', () => {
   let adminUserId: string;
   let otherAccessToken: string;
   let divisionId: string;
+  let divisionCode: string;
+  const divisionName = 'Jakarta Division';
 
   const payload = {
     code: `JKT_${Date.now().toString().slice(-6)}`,
@@ -103,11 +105,12 @@ describe('Branches (e2e)', () => {
       .post('/divisions')
       .set('Authorization', `Bearer ${adminAccessToken}`)
       .send({
-        name: 'Jakarta Division',
+        name: divisionName,
         code: `JD_${Date.now().toString().slice(-6)}`,
       })
       .expect(201);
     divisionId = (division.body as { id: string }).id;
+    divisionCode = (division.body as { code: string }).code;
   });
 
   afterAll(async () => {
@@ -137,11 +140,13 @@ describe('Branches (e2e)', () => {
       name: 'Jakarta Pusat',
       phone: '+6281234567890',
       status: 'draft',
-      createdBy: adminUserId,
+      createdBy: { id: adminUserId, username: adminUsername },
+      updatedBy: { id: adminUserId, username: adminUsername },
       latitude: null,
       nfcId: null,
-      divisionId: null,
+      division: null,
     });
+    expect(created.body).not.toHaveProperty('divisionId');
     const id = (created.body as { id: string }).id;
 
     await request(app.getHttpServer())
@@ -167,7 +172,7 @@ describe('Branches (e2e)', () => {
       .set('Authorization', `Bearer ${adminAccessToken}`)
       .expect(200);
 
-    await request(app.getHttpServer())
+    const patched = await request(app.getHttpServer())
       .patch(`/branches/${id}`)
       .set('Authorization', `Bearer ${adminAccessToken}`)
       .send({
@@ -178,6 +183,15 @@ describe('Branches (e2e)', () => {
         divisionId,
       })
       .expect(200);
+    expect(patched.body).toMatchObject({
+      name: 'Jakarta Selatan',
+      division: {
+        id: divisionId,
+        code: divisionCode,
+        name: divisionName,
+      },
+      createdBy: { id: adminUserId, username: adminUsername },
+    });
 
     await request(app.getHttpServer())
       .patch(`/branches/${id}`)