PR #29826: fix(editor): restore workflow name in window tab title (#29823)

• Repository: n8n-io/n8n
• Author: ChrisJr404
• State: open | merged: False
• Link: https://github.com/n8n-io/n8n/pull/29826

Description (problem / solution / changelog)

Summary

Fixes #29823.

When a workflow was opened in the editor the browser tab title would revert to Workflow Automation - n8n instead of showing the workflow name. The regression was introduced in #25288, which moved the workflow initialization logic out of NodeView into WorkflowLayout.

After that refactor the order of operations on first load became:

1. WorkflowLayout.onMounted -> initializeWorkflow() -> useWorkflowInitialization.openWorkflow(data) calls documentTitle.setDocumentTitle(data.name, 'IDLE').
2. isLoading flips to false, <RouterView> renders NodeView.
3. NodeView.onMounted runs documentTitle.reset(), which clobbers the title with the Workflow Automation - n8n fallback.

git blame traced the documentTitle.reset() call in NodeView.vue to PR #10999, where it ran before the in-component initialization. After the move to WorkflowLayout it now runs after that initialization and clears the value that was just set.

Fix

• Drop the documentTitle.reset() call from NodeView.onMounted. The title is now owned by useWorkflowInitialization/WorkflowLayout.
• Set the title from useWorkflowInitialization in the new-workflow and template-import flows so every entry into the editor produces a tab title that matches the workflow being edited (existing-workflow and debug paths already called setDocumentTitle).

Renames continue to update the title via WorkflowDetails.handleRename.

Test plan

• Added useWorkflowInitialization.test.ts covering:
  • existing workflow load -> setDocumentTitle(name, 'IDLE') and reset not called
  • AI builder streaming -> setDocumentTitle(name, 'AI_BUILDING')
  • new workflow load -> setDocumentTitle(newName, 'IDLE')
• pnpm test --run useDocumentTitle (13/13)
• pnpm test --run WorkflowLayout (14/14)
• pnpm test --run useWorkflowInitialization (3/3)
• pnpm typecheck clean
• pnpm lint clean on touched files

Repro before fix

1. Open any saved workflow in the editor.
2. Tab title shows Workflow Automation - n8n.

After fix

1. Open a workflow named Foo bar.
2. Tab title shows Foo bar - n8n.
3. Renaming the workflow updates the tab title.
4. Opening a new (unsaved) workflow shows the new workflow's auto-name.

Closes #29823.

Changed files

• packages/frontend/editor-ui/src/app/composables/useWorkflowInitialization.test.ts (added, +205/-0)
• packages/frontend/editor-ui/src/app/composables/useWorkflowInitialization.ts (modified, +2/-0)
• packages/frontend/editor-ui/src/app/views/NodeView.vue (modified, +0/-2)