Feat/verification

[Mmesolove]

closes #123

Completed: Emergency Freeze / Circuit Breaker Design and Implementation

Implemented an emergency-freeze mechanism for composed compliance systems using a shared circuit-breaker pattern.

What was added

• Added a design writeup covering:
  • Circuit breaker architecture and integration flow
  • Freeze authority model and security tradeoffs
  • Risks of a single admin key acting as a single point of failure
  • Potential multisig-based governance model following the custom-account/multisig approach
  • Unfreeze process and recovery flow
  • Expected runtime impact of adding a breaker check before compliance evaluation

Circuit breaker implementation

• Added a reference circuit-breaker contract that:

  • Maintains a global frozen/unfrozen state.
  • Restricts freeze and unfreeze operations to authorized administrators.
  • Provides a minimal interface for consuming contracts to check emergency status.

• Added a consuming example that:

  • Checks the circuit breaker before executing gated operations.
  • Prevents transfers/actions while the system is frozen.
  • Continues normal execution after unfreeze.

Security considerations

Covered:

• Unauthorized freeze/unfreeze attempts.
• Admin key compromise risks.
• Replay or inconsistent emergency state handling.
• Tradeoff between fast incident response and decentralized control.

Tests added

Verified:

✅ Freeze blocks an otherwise valid transfer
✅ Unfreeze restores normal operation
✅ Non-admin accounts cannot freeze or unfreeze the system

Scope

This introduces the circuit-breaker pattern as an additive emergency control mechanism. Existing compliance checks and pause mechanisms remain unchanged. Further integration with "allowlist-token", "denylist-gate", "jurisdiction-flag", and composed primitives can follow after design review.

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