Add creator list filter parse error metrics counter

[Chucks1093]

Summary
Add creator list filter parse error metrics counter

Scope

• add metrics counter for creator-list filter parse failures\n- include route and error-category labels\n- keep overhead minimal

Acceptance Criteria

• scoped change is implemented with no unrelated file churn
• docs/tests are updated where applicable
• contributor can validate the outcome locally

Contributor coordination: if you pick this up, reach out in Telegram for updates or clarification: https://t.me/accesslayerorg

[KayProject]

@KayProject has applied to work on this issue as part of the Stellar Wave Program's 4th wave.

Hi Maintainer can i work on this issue

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

[DavisVT]

@DavisVT has applied to work on this issue as part of the Stellar Wave Program's 4th wave.

pls assign this issue to me

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

[ONEONUORA]

@ONEONUORA has applied to work on this issue as part of the Stellar Wave Program's 4th wave.

Hi i am a backend developer with almost three years of experience. I am confident i can handle this issue

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

[drips-wave]

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

🧑‍💻 @DavisVT: 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

When opening a PR, please link it to this issue to ensure it gets tracked accurately. Points are awarded when this issue is marked as completed by the maintainer.

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