[BE-22] Implement POST /assets - create asset endpoint

[yusuftomilola]

Overview

Implement the create asset endpoint inside backend/contrib/. This is one of the most important endpoints in the system.

Location

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

Acceptance Criteria

• POST /assets endpoint implemented, protected by JwtAuthGuard
• CreateAssetDto with fields: name*, categoryId*, departmentId*, description?, serialNumber?, purchaseDate?, purchasePrice?, currentValue?, warrantyExpiration?, status?, condition?, location?, assignedToId?, manufacturer?, model?, tags?, notes?
• assetId auto-generated in format AST-1001, AST-1002 etc. (padded, sequential)
• AssetHistory entry created with action CREATED after successful save
• Returns the created asset with all relations loaded
• createdBy set to the currently authenticated user

[ayshadogo]

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

Hello,
I am aysha, a backend developer with experience in NestJS, ExpressJS, and Node.js.
I would like to contribute to this issue and resolve it.
Thank you.

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

[drips-wave]

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

🧑‍💻 @ayshadogo: 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.

Warning

When opening a PR, please link it to this issue to ensure it gets tracked accurately. Points are awarded when this issue is marked as completed by the maintainer.

🤠 Repo maintainers: Please keep an eye on the contributor's progress and review their work before the due date. You can manage this issue, including adjusting its complexity and points, here.

🌊 Happy Wave 🌊

[drips-wave]

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

😎 @ayshadogo: 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.

🧑‍💻 Repo maintainers: How'd the contributor do? Leave a review to share your experience working with them.