Add a circuit-breaker guard to the escrow contract's release paths

[Meshmulla]

Summary

The escrow contract (soroban/src/escrow_contract.rs) handles asset locking and release — the highest-value flow in the system. We already have a circuit_breaker module; integrating it into escrow would let us halt withdrawals instantly if an anomaly or exploit is detected, limiting blast radius.

What we'd like

• Add a circuit-breaker / pause check to the sensitive escrow entry points (release/withdraw)
• When tripped, those paths should cleanly revert with a clear error while safe read paths keep working
• An authorized role can trip and reset the breaker

Where to look

• soroban/src/escrow_contract.rs — the flows to guard
• soroban/src/circuit_breaker.rs and submission_pause.rs — existing pause/breaker primitives to reuse
• soroban/src/acl.rs — access control for who may trip/reset

Acceptance criteria

• Release/withdraw paths honor the circuit breaker and revert with a descriptive error when tripped
• Only an authorized role can trip or reset the breaker
• Read-only queries remain available while paused
• Tests cover the tripped and reset states

Notes

Reuse the existing breaker module rather than adding a parallel mechanism — consistency matters for auditing.