[Bug] Fix broken `shipments.validation.ts` with duplicate and conflicting schema declarations

[kingksjo]

Domain: Shipments

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Issue [Bug] Fix broken shipments.validation.ts with duplicate and conflicting schema declarations

Tier: 🔴 Hard

Description:

• Problem: src/modules/shipments/shipments.validation.ts is in a non-compilable state due to multiple duplicate declarations:
  1. ShipmentStatus is imported from two different sources (lines 2-3).
  2. CreateShipmentBodySchema is declared twice (lines 15-20 and 21-28) with conflicting definitions — one makes trackingNumber optional, the other required.
  3. ShipmentStatusBodySchema is declared three times (lines 40-43, 45-52, 63-73) with different shapes.
  4. ShipmentsQuerySchema alias is declared twice (lines 60-61).
     This blocks the entire shipments module from compiling.
• Implementation: Consolidate each schema to a single canonical declaration. Per the frontend compatibility guide, trackingNumber should be optional (auto-generated on the backend). The ShipmentStatusBodySchema should accept { status: ShipmentStatus }. Remove all duplicate declarations and ensure a single ShipmentStatus import source. Run npm run build to verify.

Dependencies:

• Depends on None

Acceptance Criteria:

• Each Zod schema is declared exactly once with no duplicates.
• CreateShipmentBodySchema makes trackingNumber optional.
• ShipmentStatusBodySchema is a single schema accepting { status }.
• npm run build compiles without errors.
• All shipment-related tests pass.
• Proper HTTP status codes and our standard JSON response wrapper are used.
• Edge cases (e.g., missing data, unauthorized roles) are handled gracefully.

Testing Requirements:

• Run shipment test suite (shipments.test.ts, shipments.service.test.ts, shipments.pagination.test.ts) to confirm no regressions.
• Add validation unit tests for each consolidated schema ensuring correct accept/reject behavior.
• Unit tests written for the core logic (target 80%+ coverage).
• External API calls or database connections are mocked in unit tests.
• Postman collection or Swagger spec updated (if this adds/modifies an endpoint).

PR Checklist:

• Branch is named conventionally (e.g., fix/issue-42-shipments-validation-duplicates).
• npm run lint and npm run build pass with zero warnings.
• Screenshot of passing Jest terminal logs is attached to the PR.
• Database migrations/seed scripts updated (if applicable).

[Itodo-S]

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

Please let me work on this issue; I can handle it.

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