[BACKEND] Add API-Version header to all responses

[dev-fatima-24]

Priority: medium

Description

The README specifies that all responses include an API-Version: 1 header. This should be applied globally via middleware rather than per-route.

Acceptance Criteria

• All responses include API-Version: 1 header
• Header is set in a single middleware, not duplicated per route
• Header is present on error responses (4xx, 5xx)
• Header is present on redirect responses
• Value is configurable for future version bumps

[uzochukwuV]

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

Hello, I would like to work on this issue. Can you pleased assign it to me

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

[Zarmaijemimah]

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

I’ll live to work on this issue please kindly assign thank you

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

[drips-wave]

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

🧑‍💻 @Zarmaijemimah: 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

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