fix redactSecrets stack overflow on circular references

[jackcbrown89]

Use a WeakMap to track visited objects and map them to their redacted results. This prevents infinite recursion and ensures secrets are redacted even through circular reference paths.

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Note

Medium Risk
Changes core redaction recursion to track and reuse seen objects/arrays; low behavioral surface area but could subtly affect identity/structure of returned objects for complex inputs.

Overview
Fixes redactSecrets to safely handle circular references by tracking visited objects/arrays in a WeakMap and reusing the already-redacted result to avoid infinite recursion.

Adds a regression test asserting circular structures are preserved (self-references point to the redacted clone) while still redacting secret strings.

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