[BE-16] Implement Departments CRUD endpoints

[yusuftomilola]

Overview

Implement the REST endpoints for managing departments inside backend/contrib/.

Location

All work must be inside backend/contrib/src/departments/.

Acceptance Criteria

• GET /departments — returns all departments including asset count (LEFT JOIN)
• GET /departments/:id — returns single department, 404 if not found
• POST /departments — creates department, CreateDepartmentDto with name*, description?; 409 if name taken
• PATCH /departments/:id — updates name/description
• DELETE /departments/:id — deletes department
• All write endpoints protected by JwtAuthGuard

[Jenix777]

@Jenix777 has applied to work on this issue as part of the Stellar Wave Program's 4th wave.

Hello Maintainer,

I hope you're doing well. I came across issue #581 and would like to request to be assigned to it.

I've reviewed the acceptance criteria and have a clear understanding of what's needed — implementing the full CRUD REST endpoints for departments within backend/contrib/src/departments/. This covers fetching all departments with asset count via a LEFT JOIN, retrieving a single department with a proper 404 response, creating a department with conflict handling (409 on duplicate name), updating, and deleting.

ℹ️ Repo Maintainers: To accept this application, review their application or assign @Jenix777 to this issue.

[temiport25]

@temiport25 has applied to work on this issue as part of the Stellar Wave Program's 4th wave.

can i work on this?

ℹ️ Repo Maintainers: To accept this application, review their application or assign @temiport25 to this issue.

[drips-wave]

Congratulations, @temiport25! 🎉 Your application was accepted by the repo's maintainers, and the issue is due on April 29, 2026.

🧑‍💻 @temiport25: 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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[drips-wave]

This issue has been completed by @temiport25 as part of the Stellar Wave Program's 4th Wave 🥳

😎 @temiport25: You earned 200 Points for completing this issue! After the current Wave ends, you'll be eligible for a percentage of the Wave's reward pool based on the percentage of total points you've earned. Learn more here. You can also Leave a review to share your experience working on this issue.

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