[BE-18] Add PaginationDto and standard paginated response wrapper in opsce module

[yusuftomilola]

Problem

Every list endpoint currently returns a raw array. There is no consistent pagination contract (page, limit, total) across endpoints, making frontend integration inconsistent.

Proposed Solution

Create backend/src/opsce/common/dto/pagination.dto.ts and a PaginatedResponseDto<T> generic wrapper. Use these across all list endpoints.

Acceptance Criteria

• PaginationDto has: page (default 1, min 1), limit (default 20, min 1, max 100) with @IsInt, @Min, @Max validators
• PaginatedResponseDto<T> has: data: T[], total: number, page: number, limit: number, totalPages: number
• Applied to: assets list, users list, departments list, locations list, audit log list
• A paginate(query, paginationDto) helper function created to reduce boilerplate
• All list endpoints tested to confirm they return the wrapper shape

[Jacques-codes]

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

Hiii, Good Morning Ser, I love your product, and I would love to solve this issue and solve it accurately.

Thank you for granting my request.

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

[augustine00z]

@augustine00z has applied to work on this issue as part of the Stellar Wave Program's 5th wave.

Hi, I’d like to work on this issue.
I can create the shared PaginationDto, PaginatedResponseDto, and reusable pagination helper, then apply them consistently across all listed endpoints. I’ll also add/update tests to verify validation rules and ensure every list endpoint returns the standardized paginated response shape.

ETA: 1–2 days

ℹ️ Repo Maintainers: To accept this application, review their application or assign @augustine00z to this issue.

[Jerry-Tekh]

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

Hu, maintainer I've work and get this done within the time frame.

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

[KuchiMercy]

@KuchiMercy 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. Can you assign?

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

[drips-wave]

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

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