## Summary
Introduces `definePageLayoutTab` so apps can attach a single tab (with
optional widgets) to an **existing** `pageLayout` referenced by
`pageLayoutUniversalIdentifier`. The parent layout can be standard, from
the same app, or from another app — mirroring how `defineField`
references an object via `objectUniversalIdentifier`.
This complements `definePageLayout`: use `definePageLayout` when you own
the entire layout, use `definePageLayoutTab` when you only want to add
to one.
```ts
import { definePageLayoutTab, PageLayoutTabLayoutMode } from 'twenty-sdk/define';
export default definePageLayoutTab({
universalIdentifier: 'b1b2b3b4-b5b6-4000-8000-000000000001',
pageLayoutUniversalIdentifier: 'STANDARD-OR-OTHER-APP-PAGE-LAYOUT-UUID',
title: 'Hello World',
position: 1000,
icon: 'IconWorld',
layoutMode: PageLayoutTabLayoutMode.CANVAS,
widgets: [/* ... */],
});
```
## Changes
- **twenty-shared**: new top-level `pageLayoutTabs:
PageLayoutTabManifest[]` on `Manifest`, optional
`pageLayoutUniversalIdentifier` on `PageLayoutTabManifest`, new
`SyncableEntity.PageLayoutTab`.
- **twenty-sdk**:
- new `definePageLayoutTab` + `PageLayoutTabConfig` exports;
- manifest extraction wiring (`TargetFunction.DefinePageLayoutTab`,
`ManifestEntityKey.PageLayoutTabs`);
- dev-mode label/state for the new entity;
- CLI scaffold (`getPageLayoutTabBaseFile`) + unit tests for `npx
twenty-cli add`.
- **twenty-server**: convert top-level `pageLayoutTabs` (and their
widgets) into universal flat entities in
`computeApplicationManifestAllUniversalFlatEntityMaps`. Cross-app FK
validation on `pageLayoutUniversalIdentifier` is already handled by the
existing `FlatPageLayoutTab` validator.
- **docs**: new `definePageLayoutTab` accordion in `apps/layout.mdx`
with usage example and guidance vs `definePageLayout`.
- **CI / rich-app fixture**: `extra-tab.page-layout-tab.ts` exercises
the new flow with a front-component widget; `expected-manifest.ts` and
`manifest.tests.ts` updated.
## Sync page layouts, tabs, and widgets
Adds the ability for SDK applications to synchronize `pageLayout`,
`pageLayoutTab`, and `pageLayoutWidget` entities, following the same
pattern established in #18003 for views and navigation menu items.
### Changes
**`twenty-shared`**
- New `PageLayoutManifest`, `PageLayoutTabManifest`, and
`PageLayoutWidgetManifest` types with a hierarchical structure (page
layout → tabs → widgets)
- Added `pageLayouts: PageLayoutManifest[]` to the `Manifest` type
**`twenty-sdk`**
- New `definePageLayout()` SDK function with validation for
universalIdentifier, name, and nested tabs/widgets
- Wired into the manifest extraction and build pipeline
(`DefinePageLayout` target function, `PageLayouts` entity key)
- Exported from the SDK entry point
**`twenty-server`**
- Added `pageLayout`, `pageLayoutTab`, `pageLayoutWidget` to
`APPLICATION_MANIFEST_METADATA_NAMES`
- New conversion utilities: manifest → universal flat entity for all
three entity types
- Updated `computeApplicationManifestAllUniversalFlatEntity
Charles Bochet