refactor(server)!: structured validation error responses (#28204)

* refactor(server)!: structured validation error responses

* refactor(server): clarify comment on removing duplicate HTTP response fields

* enhance validation error tests

* make path and message required

* fmt

* fix e2e test

* fmt

* feat: enhance error handling in getServerErrorMessage function

server/src/controllers/user.controller.spec.ts

@@ -43,15 +43,17 @@ describe(UserController.name, () => {
       expect(ctx.authenticate).toHaveBeenCalled();
     });
 
-    for (const key of ['email', 'name']) {
+    for (const [key, message] of [
+      ['email', 'Invalid input: expected email, received object'],
+      ['name', 'Invalid input: expected string, received null'],
+    ] as const) {
       it(`should not allow null ${key}`, async () => {
-        const dto = { [key]: null };
         const { status, body } = await request(ctx.getHttpServer())
           .put(`/users/me`)
           .set('Authorization', `Bearer token`)
-          .send(dto);
+          .send({ [key]: null });
         expect(status).toBe(400);
-        expect(body).toEqual(errorDto.badRequest());
+        expect(body).toEqual(errorDto.validationError([{ path: [key], message }]));
       });
     }