chore(engine): add exhaustiveness and sum type checking linters

[mrkaye97]

Description

Trying to help myself sleep at night more - exhaustiveness linters so if you miss a case in a switch you'll get yelled at.

Type of change

• Chore (changes which are not directly related to any business logic)

Checklist

Changes have been:

• Documented (where applicable)
• Added to CHANGELOG (where applicable) -- see Keep a Changelog

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🤖 AI Disclosure

• I acknowledge that an LLM was used in the creation of this Pull Request, in accordance with Hatchet's AI_POLICY.md.

• Details: Fable to fix all the issues

[vercel]

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Project	Deployment	Actions	Updated
hatchet-docs	Ready	Preview	Oct 15, 2026 9:48pm UTC

[greptile-apps]

Confidence Score: 5/5

[Medium impact] The PR appears safe to merge; no actionable issues were found.

Summary

Enables exhaustive and gochecksumtype and makes existing switch behavior explicit.

• Go linting now flags switches that leave enum values unstated.

_{Reviews (1) · Last reviewed commit: "fix: rm map checks" · Reviewed by Greptile}