[Wrangler/Workflows] Add warning on deploy of workflows belonging to other workers

[pombosilva]

Fixes WOR-1157.

Adds a confirmation prompt when wrangler deploy detects that a workflow being deployed already exists and belongs to a different worker. This prevents accidental overwrites of workflows between workers.

• Checks existing workflows via the /accounts/{accountId}/workflows API before deployment
• Warns the user and lists which workflows would be reassigned and their current owners
• Prompts for confirmation in interactive mode

Example Output:

⚠️ The following workflow(s) already exist and belong to different workers:
  - "my-workflow" (currently belongs to "other-worker")

Deploying will reassign these workflows to "my-worker".

Do you want to continue? (Y/n)

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• Tests
  • Tests included/updated
  • Automated tests not possible - manual testing has been completed as follows:
  • Additional testing not necessary because:
• Public documentation
  • Cloudflare docs PR(s):
  • Documentation not necessary because: Just adds a wrangler deploy check

A picture of a cute animal (not mandatory, but encouraged)

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[changeset-bot]

🦋 Changeset detected

Latest commit: 9501405

The changes in this PR will be included in the next version bump.

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Click here if you're a maintainer who wants to add another changeset to this PR

[claude]

Claude finished @pombosilva's task —— View job

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Changeset Review

Todo List:

• Read changeset guidelines
• Review .changeset/workflow-conflict-warning.md
• Validate against criteria
• Check for cute animals

---

✅ All changesets look good

The changeset file .changeset/workflow-conflict-warning.md passes all validation criteria:

1. ✅ Version Type: patch is appropriate for this safety/warning feature addition
2. ✅ Changelog Quality: Clear, meaningful description with good context about the behavior
3. ✅ Markdown Headers: No h1/h2/h3 headers present
4. ✅ Analytics: Not applicable (no analytics changes)
5. ✅ Dependabot: Not applicable
6. ✅ Experimental features: Not applicable

The changeset properly describes the new confirmation prompt behavior and helpfully explains the non-interactive/--strict flag behavior.

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Cuteness Report:

This is Nemo (probably). Vibing in their pink palace with absolutely no sense of personal space. Peak "just keep swimming" energy. The coral looks thrilled. 14/10 would definitely get stung trying to pet.

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[devin-ai-integration]

Devin Review found 1 potential issue.

View 5 additional findings in Devin Review.

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commit: 9501405

[LuisDuarte1]

LGTM from the workflows team 🚀

[vicb]

I added a few inline comments

[vicb]

Looks great

[vicb]

LGTM, thanks for the update