Harden client IP extraction for trusted proxy setups

[hman38705]

Issue 009: Harden client IP extraction for trusted proxy setups

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

Problem

x-forwarded-for is trusted without proxy trust boundaries. Attackers can spoof their IP to bypass rate limiting and IP whitelisting.

Acceptance Criteria

• Trusted proxy CIDRs are configurable\n- Spoofed headers are ignored for untrusted sources\n- Tests cover direct and proxied deployments\n- Documentation explains proxy configuration

[observerr411]

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Congratulations, @observerr411! 🎉 Your application was accepted by the repo's maintainers, and the issue is due on April 29, 2026.

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This issue has been completed by @observerr411 as part of the Stellar Wave Program's 4th Wave 🥳

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