Prevent conditional availability variables from being used at runtime (#21110)

Fixes https://github.com/twentyhq/twenty/issues/21094

Conditional availability variables (`objectMetadataItem`,
`numberOfSelectedRecords`, `objectPermissions`, operators like
`everyEquals`/`none`, etc.) are compile-time-only constructs used in
`conditionalAvailabilityExpression`. They were previously exported from
`twenty-sdk/front-component`, which let developers mistakenly import
them into runtime component code where they have no value.

- Move conditional availability variables from
`twenty-sdk/front-component` to `twenty-sdk/define`.
- Add a build-time manifest validation
(validate-conditional-availability-usage) that fails the build if these
variables are imported/used outside of
`conditionalAvailabilityExpression`.
- Update the github-connector example app to register commands via
dedicated *.command-menu-item.ts files instead of inline command config
in front components.
- Update docs (all locales) and test mocks to reflect the new import
paths.

packages/twenty-apps/community/github-connector/src/modules/github/project-item/command-menu-items/fetch-project-items.command-menu-item.ts

@@ -0,0 +1,11 @@
+import { defineCommandMenuItem, objectMetadataItem } from 'twenty-sdk/define';
+
+export default defineCommandMenuItem({
+  universalIdentifier: '719cfe1c-d570-4c8c-89e6-88671c6ba1ea',
+  frontComponentUniversalIdentifier: '7c397b0c-8b19-4fac-924a-8f6aa1dece78',
+  label: 'Fetch Project Items',
+  icon: 'IconLayoutKanban',
+  isPinned: false,
+  conditionalAvailabilityExpression:
+    objectMetadataItem.nameSingular === 'projectItem',
+});

packages/twenty-apps/community/github-connector/src/modules/github/project-item/front-components/fetch-project-items.front-component.tsx

@@ -2,7 +2,6 @@ import { useEffect, useState } from 'react';
 import { defineFrontComponent } from 'twenty-sdk/define';
 import {
   enqueueSnackbar,
-  objectMetadataItem,
   unmountFrontComponent,
   updateProgress,
 } from 'twenty-sdk/front-component';
@@ -97,12 +96,4 @@ export default defineFrontComponent({
   description: 'Fetches project items from GitHub Projects V2',
   isHeadless: true,
   component: FetchProjectItems,
-  command: {
-    universalIdentifier: '719cfe1c-d570-4c8c-89e6-88671c6ba1ea',
-    label: 'Fetch Project Items',
-    icon: 'IconLayoutKanban',
-    isPinned: false,
-    conditionalAvailabilityExpression:
-      objectMetadataItem.nameSingular === 'projectItem',
-  },
 });