Harden client IP extraction for trusted proxy setups

[hman38705]

Area: Backend
Files: services/api/src/security.rs, services/api/src/handlers.rs

Problem: x-forwarded-for is trusted without proxy trust boundaries.

Acceptance Criteria:

• Trusted proxy CIDRs are configurable.
• Spoofed headers are ignored for untrusted sources.
• Tests cover direct and proxied deployments.

[Dev-Odun-oss]

@jemilahabiodun-oss has applied to work on this issue as part of the Stellar Wave Program's 3rd wave.

please i will like to work on this issues

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Congratulations, @jemilahabiodun-oss! 🎉 Your application was accepted by the repo's maintainers, and the issue is due on March 30, 2026.

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This issue has been completed by @jemilahabiodun-oss as part of the Stellar Wave Program's 3rd Wave 🥳

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