feat: remember original URL and redirect after login (#18308)

## Summary

- Implement a return-to-path mechanism that preserves the user's
intended destination across authentication flows (login, magic link,
cross-domain redirects)
- Uses layered persistence: Jotai atom (in-memory), sessionStorage with
TTL (tab-switch resilience), URL query parameter (cross-domain
propagation)
- Includes path validation to prevent open redirects, automatic cleanup
after successful login, and comprehensive test coverage
- Replaces the unused `previousUrlState` with a robust
`returnToPathState` system

## Test plan

- [ ] Visit a deep link (e.g. `/objects/tasks`) while logged out —
should redirect to login, then back to `/objects/tasks` after logging in
- [ ] Visit an OAuth authorize link while logged out — should redirect
to login, then to the authorize page
- [ ] Test magic link flow: click sign-in link that opens new tab —
should still redirect to original destination
- [ ] Test cross-domain: visit `app.twenty.com/objects/tasks` — should
preserve path through workspace domain redirect
- [ ] Verify auth/onboarding paths are excluded from being saved as
return paths
- [ ] Verify return-to-path is cleared after successful navigation
- [ ] All 215 existing `usePageChangeEffectNavigateLocation` tests pass


Made with [Cursor](https://cursor.com)

packages/twenty-front/src/modules/app/hooks/useInitializeQueryParamState.ts

@@ -1,7 +1,9 @@
 import { useCallback } from 'react';
 
 import { billingCheckoutSessionState } from '@/auth/states/billingCheckoutSessionState';
+import { returnToPathState } from '@/auth/states/returnToPathState';
 import { type BillingCheckoutSession } from '@/auth/types/billingCheckoutSession.type';
+import { isValidReturnToPath } from '@/auth/utils/isValidReturnToPath';
 import { BILLING_CHECKOUT_SESSION_DEFAULT_VALUE } from '@/billing/constants/BillingCheckoutSessionDefaultValue';
 import deepEqual from 'deep-equal';
 import { useStore } from 'jotai';
@@ -9,7 +11,7 @@ import { useStore } from 'jotai';
 export const useInitializeQueryParamState = () => {
   const store = useStore();
   const initializeQueryParamState = useCallback(() => {
-    const handlers = {
+    const handlers: Record<string, (value: string) => void> = {
       billingCheckoutSession: (value: string) => {
         const billingCheckoutSession = store.get(
           billingCheckoutSessionState.atom,
@@ -43,6 +45,11 @@ export const useInitializeQueryParamState = () => {
           );
         }
       },
+      returnToPath: (value: string) => {
+        if (isValidReturnToPath(value)) {
+          store.set(returnToPathState.atom, value);
+        }
+      },
     };
 
     const queryParams = new URLSearchParams(window.location.search);