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-sdk/src/cli/utilities/dev/orchestrator/steps/__tests__/format-sync-actions-summary.spec.ts

@@ -10,6 +10,12 @@ describe('formatSyncActionsSummary', () => {
     ]);
   });
 
+  it('reports no changes when actions are missing from the response', () => {
+    expect(formatSyncActionsSummary(undefined)).toEqual([
+      { message: 'No metadata changes', status: 'info' },
+    ]);
+  });
+
   it('summarizes created, updated and deleted actions with their identifiers', () => {
     const events = formatSyncActionsSummary([
       {

packages/twenty-sdk/src/cli/utilities/dev/orchestrator/steps/format-sync-actions-summary.ts

@@ -24,15 +24,17 @@ const getActionLabel = (action: SyncAction): string => {
 };
 
 export const formatSyncActionsSummary = (
-  actions: SyncAction[],
+  actions: SyncAction[] | undefined,
 ): OrchestratorStateStepEvent[] => {
-  if (actions.length === 0) {
+  const definedActions = actions ?? [];
+
+  if (definedActions.length === 0) {
     return [{ message: 'No metadata changes', status: 'info' }];
   }
 
   const counts = { create: 0, update: 0, delete: 0 };
 
-  for (const action of actions) {
+  for (const action of definedActions) {
     counts[action.type] += 1;
   }
 
@@ -46,7 +48,7 @@ export const formatSyncActionsSummary = (
     { message: `Metadata changes: ${summaryParts.join(', ')}`, status: 'info' },
   ];
 
-  const visibleActions = actions.slice(0, MAX_DETAIL_LINES);
+  const visibleActions = definedActions.slice(0, MAX_DETAIL_LINES);
 
   for (const action of visibleActions) {
     events.push({
@@ -55,7 +57,7 @@ export const formatSyncActionsSummary = (
     });
   }
 
-  const hiddenCount = actions.length - visibleActions.length;
+  const hiddenCount = definedActions.length - visibleActions.length;
 
   if (hiddenCount > 0) {
     events.push({