Add request body schema validation with Zod and replace ad-hoc checks across routes

[thlpkee20-wq]

Description

Routes use a mix of inline checks and ad-hoc validators. Centralize on Zod schemas per route, with a single validateBody(schema) middleware producing uniform error envelopes.

Requirements and context

• Must be secure, tested, and documented
• Should be efficient and easy to review
• Relevant code: src/middleware/validation.ts, src/routes/
• Migrate routes incrementally; keep one PR per route group

Suggested execution

• Fork the repo and create a branch
• git checkout -b refactor/zod-body-validation
• Implement changes
  • Add Zod dependency and shared error formatter
  • Migrate slots and booking-intent routes first
  • Document schema-per-route convention
• Validate security and correctness assumptions

Test and commit

• Run tests
  • npm test
• Cover edge cases
  • Extra unknown fields are stripped, not silently accepted
• Include test output and notes

Example commit message

refactor: Zod schemas and unified body validation

Guidelines

• Minimum 95 percent test coverage
• Clear documentation
• Timeframe: 96 hours

[DammyAji]

@DammyAji has applied to work on this issue as part of the Stellar Wave Program's 5th wave.

Hi maintainer I'd like to work on this issue. Please kindly assign to me. Thank you.

ℹ️ Repo Maintainers: To accept this application, review their application or assign @DammyAji to this issue.

[drips-wave]

Congratulations, @DammyAji! 🎉 Your application was accepted by the repo's maintainers, and the issue is due on June 2, 2026.

🧑‍💻 @DammyAji: Please resolve the issue such that the repo's maintainers have enough time to review your contribution before the due date. You'll earn Points for completing the issue on-time, which will make you eligible for a share of the Stellar Wave Program's reward pool.

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