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/utils/patchMetadataStoreFromSSEEvent.ts

@@ -1,4 +1,3 @@
-import { metadataCollectionHashesState } from '@/metadata-store/states/metadataCollectionHashesState';
 import {
   metadataStoreState,
   type MetadataEntityKey,
@@ -22,19 +21,29 @@ type SSEEventOperation =
       deletedRecordId: string;
     };
 
-export const patchMetadataStoreFromSSEEvent = (
-  store: JotaiStore,
-  entityKey: MetadataEntityKey,
-  operation: SSEEventOperation,
-  updatedCollectionHash?: string,
-) => {
+export const patchMetadataStoreFromSSEEvent = ({
+  store,
+  entityKey,
+  operation,
+  updatedCollectionHash,
+}: {
+  store: JotaiStore;
+  entityKey: MetadataEntityKey;
+  operation: SSEEventOperation;
+  updatedCollectionHash?: string;
+}) => {
   const entry = store.get(metadataStoreState.atomFamily(entityKey));
   const currentItems = entry.current as Array<{ id: string }>;
 
+  const hashUpdate = isDefined(updatedCollectionHash)
+    ? { currentCollectionHash: updatedCollectionHash }
+    : {};
+
   switch (operation.type) {
     case 'create': {
       store.set(metadataStoreState.atomFamily(entityKey), {
         ...entry,
+        ...hashUpdate,
         current: [...currentItems, operation.createdRecord],
       });
       break;
@@ -42,6 +51,7 @@ export const patchMetadataStoreFromSSEEvent = (
     case 'update': {
       store.set(metadataStoreState.atomFamily(entityKey), {
         ...entry,
+        ...hashUpdate,
         current: currentItems.map((item) =>
           item.id === (operation.updatedRecord as { id: string }).id
             ? { ...item, ...operation.updatedRecord }
@@ -53,6 +63,7 @@ export const patchMetadataStoreFromSSEEvent = (
     case 'delete': {
       store.set(metadataStoreState.atomFamily(entityKey), {
         ...entry,
+        ...hashUpdate,
         current: currentItems.filter(
           (item) => item.id !== operation.deletedRecordId,
         ),
@@ -60,13 +71,4 @@ export const patchMetadataStoreFromSSEEvent = (
       break;
     }
   }
-
-  if (isDefined(updatedCollectionHash)) {
-    const currentHashes = store.get(metadataCollectionHashesState.atom);
-
-    store.set(metadataCollectionHashesState.atom, {
-      ...currentHashes,
-      [entityKey]: updatedCollectionHash,
-    });
-  }
 };