refactor: metadata store cleanup, SSE unification, mock metadata loading & login redirect fix (#18651)

## Summary
- **SSE unification**: Replaced 11 individual SSE effect components with
a single generic `MetadataStoreSSEEffect`
- **Metadata store cleanup**: Merged `metadataCollectionHashesState`
into `metadataStoreState` (currentCollectionHash / draftCollectionHash
per entity), moved `objectMetadataItemsSelector` to `object-metadata`
domain, converted `navigationMenuItemsState` to a derived selector
- **Naming clarity**: Renamed `isAppMetadataReadyState` →
`isMinimalMetadataReadyState`, `MetadataGater` → `MinimalMetadataGater`,
`useIsLogged` → `useHasAccessTokenPair`,
`patchMetadataStoreFromSSEEvent` now takes named object params
- **Mock metadata loading**: Added `generate-navigation-menu-items.ts`
script, rewrote `useLoadMockedMinimalMetadata` to load full
objects/fields/indexes/views/navItems from generated mock data, enabling
proper sign-in background rendering (table columns, view picker,
navigation)
- **Login/logout transitions**: `MinimalMetadataLoadEffect` manages
mocked↔real metadata transitions based on auth state,
`MainContextStoreProvider` computes context on auth pages for view
picker support
- **Login redirect fix**: `handleLoadWorkspaceAfterAuthentication` now
re-enables `isAppEffectRedirectEnabled` after `loadCurrentUser()`
completes, fixing the blocked post-login navigation
- **Dead code removal**: Deleted `useRefreshPageLayouts`,
`useApplyPageLayouts`, `useStaleMetadataEntities`,
`metadataCollectionHashesState`, and all individual SSE effects

## Test plan
- [x] Login from welcome page redirects to companies page
- [x] Logout transitions cleanly to mocked metadata on welcome page
- [x] Sign-in background shows table columns, view picker, and
navigation items
- [x] SSE events still update metadata store entries correctly
- [x] Navigation menu items persist across page refreshes
- [ ] CI: lint, typecheck, tests pass

packages/twenty-front/src/modules/metadata-store/components/MinimalMetadataGater.tsx

@@ -1,9 +1,7 @@
 import React from 'react';
 
-import { isAppMetadataReadyState } from '@/metadata-store/states/isAppMetadataReadyState';
-import { useIsLogged } from '@/auth/hooks/useIsLogged';
+import { isMinimalMetadataReadyState } from '@/metadata-store/states/isMinimalMetadataReadyState';
 import { useDateTimeFormat } from '@/localization/hooks/useDateTimeFormat';
-import { objectMetadataItemsState } from '@/object-metadata/states/objectMetadataItemsState';
 import { useAtomStateValue } from '@/ui/utilities/state/jotai/hooks/useAtomStateValue';
 import { UserContext } from '@/users/contexts/UserContext';
 import { useLocation } from 'react-router-dom';
@@ -11,10 +9,8 @@ import { AppPath } from 'twenty-shared/types';
 import { UserOrMetadataLoader } from '~/loading/components/UserOrMetadataLoader';
 import { isMatchingLocation } from '~/utils/isMatchingLocation';
 
-export const MetadataGater = ({ children }: React.PropsWithChildren) => {
-  const isAppMetadataReady = useAtomStateValue(isAppMetadataReadyState);
-  const objectMetadataItems = useAtomStateValue(objectMetadataItemsState);
-  const isLoggedIn = useIsLogged();
+export const MinimalMetadataGater = ({ children }: React.PropsWithChildren) => {
+  const isMinimalMetadataReady = useAtomStateValue(isMinimalMetadataReadyState);
   const location = useLocation();
 
   const { dateFormat, timeFormat, timeZone } = useDateTimeFormat();
@@ -22,11 +18,12 @@ export const MetadataGater = ({ children }: React.PropsWithChildren) => {
   const isOnExcludedPath =
     isMatchingLocation(location, AppPath.Verify) ||
     isMatchingLocation(location, AppPath.VerifyEmail) ||
+    isMatchingLocation(location, AppPath.SignInUp) ||
+    isMatchingLocation(location, AppPath.Invite) ||
+    isMatchingLocation(location, AppPath.ResetPassword) ||
     isMatchingLocation(location, AppPath.CreateWorkspace);
 
-  const shouldShowLoader =
-    (!isAppMetadataReady && isLoggedIn && !isOnExcludedPath) ||
-    objectMetadataItems.length === 0;
+  const shouldShowLoader = !isMinimalMetadataReady && !isOnExcludedPath;
 
   if (shouldShowLoader) {
     return <UserOrMetadataLoader />;