Add input sanitization for query and path parameters

[therealjhay]

Current behavior:
Body sanitization exists but query parameters and path params are not sanitized for control characters.

Expected behavior:
Add preHandler hook that sanitizes all req.query and req.params string values: remove null bytes (\x00), newlines, other ASCII control characters (0x00–0x1F except \t). Log warning when sanitization applied.

Files to modify:

• services/api-gateway/src/index.ts — add sanitization hook

Test requirements:

1. Send query param with null byte — sanitized, warning logged.
2. Send clean query param — no warning.

Acceptance criteria:

• Control characters removed from query and path params.
• No impact on legitimate requests.

[emmyokolo2525-cyber]

Hi maintainer, I'd like to work on issue. I'll keep the scope aligned with the current architecture and submit a focused, reviewable PR.

[Flashweb1]

@Flashweb1 has applied to work on this issue as part of the Stellar Wave Program's 7th wave.

Hello maintainer, I’d like to work on this issue. I’ve reviewed the problem statement and understand the requirements. I’m ready to get started and will submit a clean, well-tested solution. Thank you for the opportunity.

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[Oyinkans0la12]

@Oyinkans0la12 has applied to work on this issue as part of the Stellar Wave Program's 7th wave.

Can i work on this please?

ℹ️ Repo Maintainers: To accept this application, review their application or assign @Oyinkans0la12 to this issue.

[drips-wave]

Congratulations, @Oyinkans0la12! 🎉 Your application was accepted by the repo's maintainers, and the issue is due on July 30, 2026.

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[drips-wave]

This issue has been completed by @Oyinkans0la12 as part of the Stellar Wave Program's 7th Wave 🥳

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