fix: eliminate workflow editing flicker on active-to-draft transitions (#21176)

## Before

https://github.com/user-attachments/assets/5108a9d8-2017-41d5-855c-98714cbd4237

## After

https://github.com/user-attachments/assets/0a78d1e1-354f-4f3f-8ec4-6f46517619e4

## Summary
- Fixes visual flickering/glitching in the workflow show page header and
canvas when editing an active workflow or discarding a draft
- Root cause: SSE events re-added discarded drafts to Apollo cache, and
multiple hook instances had independent state causing version
oscillation between DRAFT and ACTIVE
- Rewrites `useWorkflowWithCurrentVersion` with a module-level
`discardedDraftId` variable shared across all instances, Apollo cache
seeding in mutation callbacks, and `lastValidResult` caching to prevent
null renders

## Test plan
- [x] Open a workflow show page with an ACTIVE workflow
- [x] Drag a node to change position → verify no flicker, status shows
DRAFT smoothly
- [x] Discard the draft → verify header does NOT flicker between
DRAFT/ACTIVE, position resets cleanly
- [x] Click on manual trigger and edit settings → verify the edit works
(draft created, settings saved)
- [x] Repeat discard + edit cycle multiple times to confirm stability

packages/twenty-front/src/modules/workflow/hooks/useWorkflowWithCurrentVersion.ts

@@ -1,9 +1,5 @@
-import { useEffect } from 'react';
-
 import { useFindOneRecord } from '@/object-record/hooks/useFindOneRecord';
-import { useAtomFamilyStateValue } from '@/ui/utilities/state/jotai/hooks/useAtomFamilyStateValue';
-import { useSetAtomFamilyState } from '@/ui/utilities/state/jotai/hooks/useSetAtomFamilyState';
-import { shouldWorkflowRefetchRequestFamilyState } from '@/workflow/states/shouldWorkflowRefetchRequestFamilyState';
+import { useEffectiveDraftVersionId } from '@/workflow/hooks/useEffectiveDraftVersionId';
 import {
   type Workflow,
   type WorkflowVersion,
@@ -21,62 +17,45 @@ type WorkflowWithAllVersions = Omit<Workflow, 'versions'> & {
 export const useWorkflowWithCurrentVersion = (
   workflowId: string | undefined,
 ): WorkflowWithCurrentVersion | undefined => {
-  const shouldWorkflowRefetchRequest = useAtomFamilyStateValue(
-    shouldWorkflowRefetchRequestFamilyState,
-    workflowId ?? '',
-  );
-  const setShouldWorkflowRefetchRequest = useSetAtomFamilyState(
-    shouldWorkflowRefetchRequestFamilyState,
-    workflowId ?? '',
-  );
-
-  const { record: workflow, refetch: refetchWorkflow } =
-    useFindOneRecord<WorkflowWithAllVersions>({
-      objectNameSingular: CoreObjectNameSingular.Workflow,
-      objectRecordId: workflowId,
-      recordGqlFields: {
+  const { record: workflow } = useFindOneRecord<WorkflowWithAllVersions>({
+    objectNameSingular: CoreObjectNameSingular.Workflow,
+    objectRecordId: workflowId,
+    recordGqlFields: {
+      id: true,
+      name: true,
+      statuses: true,
+      lastPublishedVersionId: true,
+      versions: {
         id: true,
+        status: true,
         name: true,
-        statuses: true,
-        lastPublishedVersionId: true,
-        versions: {
-          id: true,
-          status: true,
-          name: true,
-          createdAt: true,
-        },
+        createdAt: true,
       },
-      skip: !isDefined(workflowId),
-    });
+    },
+    skip: !isDefined(workflowId),
+  });
 
-  useEffect(() => {
-    if (shouldWorkflowRefetchRequest) {
-      setShouldWorkflowRefetchRequest(false);
-      refetchWorkflow();
-    }
-  }, [
-    shouldWorkflowRefetchRequest,
-    setShouldWorkflowRefetchRequest,
-    refetchWorkflow,
-  ]);
-
-  const draftVersion = workflow?.versions.find(
+  const draftVersionFromServer = workflow?.versions.find(
     (workflowVersion) => workflowVersion.status === 'DRAFT',
   );
 
-  const workflowVersions = [...(workflow?.versions ?? [])];
+  const { effectiveDraftId, lastDiscardedDraftId } = useEffectiveDraftVersionId(
+    draftVersionFromServer,
+  );
 
-  workflowVersions.sort((a, b) => (a.createdAt > b.createdAt ? -1 : 1));
+  const workflowVersions = [...(workflow?.versions ?? [])]
+    .filter((version) => version.id !== lastDiscardedDraftId)
+    .sort((a, b) => (a.createdAt > b.createdAt ? -1 : 1));
 
   const latestVersion = workflowVersions[0];
 
-  const currentVersionWithoutSteps = draftVersion ?? latestVersion;
+  const currentVersionId = effectiveDraftId ?? latestVersion?.id;
 
   const { record: currentVersionWithSteps } = useFindOneRecord<WorkflowVersion>(
     {
       objectNameSingular: CoreObjectNameSingular.WorkflowVersion,
-      objectRecordId: currentVersionWithoutSteps?.id,
-      skip: !isDefined(currentVersionWithoutSteps?.id),
+      objectRecordId: currentVersionId,
+      skip: !isDefined(currentVersionId),
     },
   );