26. Standardize backend responses with a global validation pipe and API envelope

[Cedarich]

Area: Backend
Complexity: Easy

Summary:
Align the active backend with its documented conventions for input validation and response shape.

Acceptance Criteria:

• Global request validation is enabled.
• Active routes return a consistent envelope where intended.
• Invalid payloads fail with predictable formatting.

[Ayinkx]

Hi i would like to work on this issue please assign to me
I can do it perfectly

[Purity-Euphemia]

Good Day Maintainer, I have experience and would review the issue, implement a clean solution, test it, and submit a pull request.

[Ayinkx01]

Hi l would like to take this job

[Ayinkx01]

Hi l would like to take this job

[datagerl]

Hey maintainer can I please work on this issue.