fix(sdk): link dev UI to workspace application detail page (#20849)

sdk handle auth of one workspace per session -- but server could be
configured as multi or single -- hence for multi get subdomain -- and
for single the localhost fallback!
also: link includes applicationId so it opens the app detail page
directly (not the list)

## QA
multi workspace flag on -

<img width="2996" height="1712" alt="CleanShot 2026-05-22 at 18 21
31@2x"
src="https://github.com/user-attachments/assets/8499b9f3-b22e-45e2-8b97-4b27fadc3c94"
/>

multi workspace flag off - 

<img width="3012" height="1734" alt="CleanShot 2026-05-22 at 18 14
37@2x"
src="https://github.com/user-attachments/assets/3af2f492-5e2d-4a4b-8251-c3343d79ae9e"
/>

packages/twenty-sdk/src/cli/__tests__/integration/utils/setup-app-dev-mocks.ts

@@ -2,6 +2,7 @@ import { vi } from 'vitest';
 
 const mockApiService = {
   validateAuth: vi.fn().mockResolvedValue({ authValid: true, serverUp: true }),
+  getWorkspaceFrontendUrl: vi.fn().mockResolvedValue('http://localhost:3000'),
   generateApplicationToken: vi.fn().mockResolvedValue({
     success: true,
     data: {
@@ -37,6 +38,7 @@ const mockApiService = {
 vi.mock('@/cli/utilities/api/api-service', () => ({
   ApiService: class {
     validateAuth = mockApiService.validateAuth;
+    getWorkspaceFrontendUrl = mockApiService.getWorkspaceFrontendUrl;
     generateApplicationToken = mockApiService.generateApplicationToken;
     refreshToken = mockApiService.refreshToken;
     findApplicationRegistrationByUniversalIdentifier =