Add helper for masking sensitive fields before writing objects to structured logs

[Chucks1093]

Summary

Structured logs occasionally include objects that contain sensitive fields like wallet addresses, callback URLs, or API keys. A shared masking helper that accepts an object and a list of field names to mask should be applied before any object is written to a log.

Scope

• Add maskFields(obj: Record<string, unknown>, fields: string[]): Record<string, unknown> helper
• Replaces the value of each named field with [REDACTED]
• Works recursively for nested objects
• Does not mutate the original object
• Add unit tests for: top-level field masked, nested field masked, non-existent field ignored, original object unchanged

Acceptance Criteria

• Named fields replaced with [REDACTED]
• Nested fields masked correctly
• Original object not mutated
• Non-existent field names ignored without error

ETA: 12 hours

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Coordinate on Telegram

[heymide]

I can take this on. I've gone through the details and will provide a well-tested solution aligned with the project standards.

[OpensrcLord]

Hello @maintainer, I understand the expected outcome and would love to work on this. I'll provide a solution that satisfies the acceptance criteria.

[mitchellecm7]

Hi Maintainer, reviewed the issue and I'm confident I can handle this — solid background across full stack development. Happy to hop on this and get a PR up quickly. Please assign to me

[grantfox-oss]

🦊 GrantFox — @mitchellecm7 has been assigned to this issue as part of the Official Campaign | FWC26 campaign!

Next steps:

1. Open a Pull Request referencing this issue (e.g., Closes #569)
2. Your PR will be reviewed by the accesslayerorg maintainers

Good luck! Track your progress on GrantFox.