feat(app-dev): add dry-run preview to dev sync (#21251)

Split out of #21240. Stacked on #21250 (review/merge that first).

`yarn twenty dev --once --dry-run` computes the migration plan and
prints the diff **without applying anything** (no migration, no
app-record update, no SDK generation). Also renders the diff on a normal
`dev --once` sync.

<img width="646" height="179" alt="image"
src="https://github.com/user-attachments/assets/59f3ddcd-2a5b-4b8a-b21a-c659abe16af0"
/>

packages/twenty-server/test/integration/metadata/suites/application/utils/sync-application.util.ts

@@ -14,15 +14,18 @@ export const syncApplication = async ({
   manifest,
   expectToFail = false,
   token,
+  dryRun,
 }: {
   manifest: Manifest;
   expectToFail?: boolean;
   token?: string;
+  dryRun?: boolean;
 }): CommonResponseBody<{
   syncApplication: WorkspaceMigration;
 }> => {
   const graphqlOperation = syncApplicationQueryFactory({
     manifest,
+    dryRun,
   });
 
   const response = await makeMetadataAPIRequest(graphqlOperation, token);