test: drop mocks of removed getUserIdFromRequest helper

The integration tests landed on main after this branch was cut and
mocked the helper this PR deletes. Vitest factory mocks don't validate
against the real module shape, so the extra key was harmless but
misleading.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

backend/src/__tests__/integration/chat.routes.test.ts

@@ -41,7 +41,6 @@ function mockSupabase() {
 
 vi.mock("../../lib/supabase", () => ({
     createServerSupabase: vi.fn(() => mockSupabase()),
-    getUserIdFromRequest: vi.fn(async () => "u1"),
 }));
 
 // Authenticate every request as user "u1" without exercising the real Supabase

backend/src/__tests__/integration/documentsUpload.routes.test.ts

@@ -25,7 +25,6 @@ function mockSupabase() {
 
 vi.mock("../../lib/supabase", () => ({
     createServerSupabase: vi.fn(() => mockSupabase()),
-    getUserIdFromRequest: vi.fn(async () => "u1"),
 }));
 
 vi.mock("../../middleware/auth", () => ({

backend/src/__tests__/integration/projectChat.routes.test.ts

@@ -38,7 +38,6 @@ function mockSupabase() {
 
 vi.mock("../../lib/supabase", () => ({
     createServerSupabase: vi.fn(() => mockSupabase()),
-    getUserIdFromRequest: vi.fn(async () => "u1"),
 }));
 
 vi.mock("../../middleware/auth", () => ({

backend/src/__tests__/integration/projects.routes.test.ts

@@ -68,7 +68,6 @@ function mockSupabase() {
 
 vi.mock("../../lib/supabase", () => ({
     createServerSupabase: vi.fn(() => mockSupabase()),
-    getUserIdFromRequest: vi.fn(async () => "u1"),
 }));
 
 vi.mock("../../middleware/auth", () => ({

backend/src/__tests__/integration/tabular.routes.test.ts

@@ -81,7 +81,6 @@ function mockSupabase() {
 
 vi.mock("../../lib/supabase", () => ({
     createServerSupabase: vi.fn(() => mockSupabase()),
-    getUserIdFromRequest: vi.fn(async () => "u1"),
 }));
 
 vi.mock("../../middleware/auth", () => ({

backend/src/__tests__/integration/user.routes.test.ts

@@ -106,7 +106,6 @@ function mockSupabase() {
 
 vi.mock("../../lib/supabase", () => ({
     createServerSupabase: vi.fn(() => mockSupabase()),
-    getUserIdFromRequest: vi.fn(async () => "u1"),
 }));
 
 // requireAuth always authenticates u1. requireMfaIfEnrolled is a reconfigurable