feat: enable policy verification guardrail

[gebhardtr]

Description

Adds a policy engine and first policy to gate PRs/merges that drop code coverage below 90%.

Fixes # (issue)

Type of change

Please delete options that are not relevant.

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

How Has This Been Tested?

Please describe the tests that you ran to verify your changes. Provide instructions so we can reproduce. Please also list any relevant details for your test configuration

• Test A
• Test B

Test Configuration:

• Firmware version:
• Hardware:
• Toolchain:
• SDK:

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• Any dependent changes have been merged and published in downstream modules

[dustin-sale]

Review by @dustin-sale via Codex.

Requested changes

No blocking changes requested.

Additional review notes

• Please add repository agent context for the new policy/ area, linked from AGENTS.md. Cover the gate’s scope, its trusted-base execution model, and the required local validation when changing the verifier, Cedar policy/schema, or dependencies. Make explicit that CI runs the approved base verifier, so candidate changes to the policy implementation require separate validation before merge.
• Hosted enforcement remains subject to the activation and disposable-PR checks documented in policy/README.md.

Validation

All 10 policy regression tests, repository lint, locked dependency installation, and diff checks passed. The actual PR merge ref had the expected parents and passed verifier evaluation. The new policy workflow has not yet been exercised on GitHub.

No inline comments proposed.