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/app/components/AppRouterProviders.tsx

@@ -1,12 +1,12 @@
 import { AgentChatProvider } from '@/ai/components/AgentChatProvider';
 import { CommandMenuConfirmationModalManager } from '@/command-menu-item/confirmation-modal/components/CommandMenuConfirmationModalManager';
 import { ApolloProvider } from '@/apollo/components/ApolloProvider';
-import { MetadataGater } from '@/metadata-store/components/MetadataGater';
-import { IsAppMetadataReadyEffect } from '@/metadata-store/effect-components/IsAppMetadataReadyEffect';
+import { MinimalMetadataGater } from '@/metadata-store/components/MinimalMetadataGater';
+import { IsMinimalMetadataReadyEffect } from '@/metadata-store/effect-components/IsMinimalMetadataReadyEffect';
 
 import { GotoHotkeysEffectsProvider } from '@/app/effect-components/GotoHotkeysEffectsProvider';
 import { MinimalMetadataLoadEffect } from '@/metadata-store/effect-components/MinimalMetadataLoadEffect';
-import { MetadataProviderInitialEffects } from '@/metadata-store/effect-components/MetadataProviderInitialEffects';
+import { UserMetadataProviderInitialEffect } from '@/metadata-store/effect-components/UserMetadataProviderInitialEffect';
 import { PageChangeEffect } from '@/app/effect-components/PageChangeEffect';
 import { AuthProvider } from '@/auth/components/AuthProvider';
 import { CaptchaProvider } from '@/captcha/components/CaptchaProvider';
@@ -31,7 +31,6 @@ import { BaseThemeProvider } from '@/ui/theme/components/BaseThemeProvider';
 import { UserThemeProviderEffect } from '@/ui/theme/components/UserThemeProviderEffect';
 import { PageFavicon } from '@/ui/utilities/page-favicon/components/PageFavicon';
 import { PageTitle } from '@/ui/utilities/page-title/components/PageTitle';
-import { LazyMetadataLoadEffect } from '@/users/components/LazyMetadataLoadEffect';
 import { WorkspaceProviderEffect } from '@/workspace/components/WorkspaceProviderEffect';
 import { StrictMode } from 'react';
 import { Outlet, useLocation } from 'react-router-dom';
@@ -45,16 +44,15 @@ export const AppRouterProviders = () => {
     <ApolloProvider>
       <BaseThemeProvider>
         <ClientConfigProviderEffect />
+        <UserMetadataProviderInitialEffect />
         <MinimalMetadataLoadEffect />
-        <MetadataProviderInitialEffects />
-        <LazyMetadataLoadEffect />
-        <IsAppMetadataReadyEffect />
+        <IsMinimalMetadataReadyEffect />
         <WorkspaceProviderEffect />
         <ClientConfigProvider>
           <CaptchaProvider>
             <ChromeExtensionSidecarEffect />
             <ChromeExtensionSidecarProvider>
-              <MetadataGater>
+              <MinimalMetadataGater>
                 <AuthProvider>
                   <ApolloCoreProvider>
                     <SSEProvider>
@@ -88,7 +86,7 @@ export const AppRouterProviders = () => {
                     </SSEProvider>
                   </ApolloCoreProvider>
                 </AuthProvider>
-              </MetadataGater>
+              </MinimalMetadataGater>
             </ChromeExtensionSidecarProvider>
           </CaptchaProvider>
         </ClientConfigProvider>