Add v2 onboarding loading screen while creating workspace (#22152)

https://github.com/user-attachments/assets/cc7b1d10-7495-4f21-9311-4c22c0f14771

Adds the full-screen loading screen shown while a new workspace is being
created in the v2 sign-up flow (`SignInUpV2`), building on the v2
"Create your workspace" step.

How it works:
- Submitting the v2 create-workspace form marks the flow as v2
(`isOnboardingV2State`) and creates the workspace. The flag is carried
across the cross-subdomain redirect with an `onboardingV2=true` URL
param, so v2 users land on a new `/workspace-activation-v2` route
instead of v1's `/workspace-activation`.
- `WorkspaceActivationV2` runs the real `activateWorkspace` mutation on
mount and renders the loader: a pulsing Twenty logomark above a stack of
status messages that shift up one at a time, cycling once per second.
There is no faked/minimum duration; it advances to the next onboarding
step as soon as the workspace is activated.
- On activation failure it shows a "Workspace creation failed" screen
with a Retry button.

v1 onboarding is unchanged. Storybook:
`Modules/Auth/SignInUpWorkspaceActivationV2`.

Note: The flashes will be fixed in later PRs

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packages/twenty-front/src/hooks/__tests__/usePageChangeEffectNavigateLocation.test.ts

@@ -85,6 +85,7 @@ const setupMockState = (
   calendarBookingPageId?: string | null,
   returnToPath?: string,
   currentWorkspace: object | null = { id: 'mock-workspace-id' },
+  isOnboardingV2 = false,
 ) => {
   jest
     .mocked(useAtomStateValue)
@@ -92,7 +93,8 @@ const setupMockState = (
     .mockReturnValueOnce(calendarBookingPageId ?? 'mock-calendar-id')
     .mockReturnValueOnce([{ namePlural: objectNamePlural ?? '' }])
     .mockReturnValueOnce(verifyEmailRedirectPath)
-    .mockReturnValueOnce(returnToPath ?? '');
+    .mockReturnValueOnce(returnToPath ?? '')
+    .mockReturnValueOnce(isOnboardingV2);
 };
 
 // prettier-ignore
@@ -454,3 +456,37 @@ describe('usePageChangeEffectNavigateLocation — authenticated with no current
     },
   );
 });
+
+describe('usePageChangeEffectNavigateLocation — onboarding V2', () => {
+  const setupWorkspaceActivationV2Case = (loc: AppPath) => {
+    setupMockIsMatchingLocation(loc);
+    setupMockOnboardingStatus(OnboardingStatus.WORKSPACE_ACTIVATION);
+    setupMockIsWorkspaceActivationStatusEqualsTo(false);
+    setupMockHasAccessTokenPair(true);
+    setupMockIsOnAWorkspace(true);
+    setupMockUseQuery();
+    setupMockUseParams();
+    setupMockState(
+      undefined,
+      undefined,
+      undefined,
+      undefined,
+      { id: 'mock-workspace-id' },
+      true,
+    );
+  };
+
+  it('routes to WorkspaceActivationV2 when onboardingV2 is active and status is WORKSPACE_ACTIVATION', () => {
+    setupWorkspaceActivationV2Case(AppPath.SignInUpV2);
+
+    expect(usePageChangeEffectNavigateLocation()).toEqual(
+      AppPath.WorkspaceActivationV2,
+    );
+  });
+
+  it('does not redirect away from the WorkspaceActivationV2 page during activation', () => {
+    setupWorkspaceActivationV2Case(AppPath.WorkspaceActivationV2);
+
+    expect(usePageChangeEffectNavigateLocation()).toBeUndefined();
+  });
+});