[codex] Mask secrets in guardrail bash output

[terisuke]

Summary

• mask common secret formats from guardrail-managed bash output before later hooks process it
• record a secret_masked event when redaction happens
• add a direct hook regression test for AWS/OpenAI-style output redaction
• widen hasCodexMcp inference so the mutable guardrail context typechecks cleanly

Validation

• bun test test/plugin/guardrail-secret-mask.test.ts test/plugin/guardrail-review.test.ts test/plugin/guardrail-access.test.ts (from packages/opencode)
• bun typecheck (from packages/opencode)
• git diff --check
• opencode --version
• node packages/guardrails/bin/opencode-guardrails --version
• local symlink check for ~/.config/opencode/plugins/guardrail.ts
• push hook: bun turbo typecheck

[github-actions]

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[github-actions]

Hey! Your PR title [codex] Mask secrets in guardrail bash output doesn't follow conventional commit format.

Please update it to start with one of:

• feat: or feat(scope): new feature
• fix: or fix(scope): bug fix
• docs: or docs(scope): documentation changes
• chore: or chore(scope): maintenance tasks
• refactor: or refactor(scope): code refactoring
• test: or test(scope): adding or updating tests

Where scope is the package name (e.g., app, desktop, opencode).

See CONTRIBUTING.md for details.

[Copilot]

Pull request overview

This PR adds secret redaction for guardrail-managed bash tool output so downstream hooks don’t process or persist common secret formats, and emits a secret_masked event when redaction occurs.

Changes:

• Redact common secret patterns from bash output in the guardrail plugin and emit a secret_masked event with a count.
• Add a regression test ensuring AWS/OpenAI-style secrets in bash output are redacted and the event is recorded.
• Widen hasCodexMcp typing in the guardrail context to avoid overly-narrow literal inference.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 3 comments.

File	Description
packages/opencode/test/plugin/guardrail-secret-mask.test.ts	New regression test validating bash-output secret masking + secret_masked event emission.
packages/guardrails/profile/plugins/guardrail.ts	Implements bash-output secret masking and records a secret_masked event on redaction.
packages/guardrails/profile/plugins/guardrail-context.ts	Adjusts hasCodexMcp typing to widen the inferred type for mutable context usage.

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