# Task 4: Define backend security and refactor strategy from latest audit

Status: pending  
Priority: high  
Source audit: `.taskmaster/docs/audit-backend-stack-security-and-refactor-assessment-2026-05-24.md`

Convert the backend stack security/refactor assessment into concrete architecture decisions, documentation deliverables, and developer handoff criteria.

This is an advisory/architecture task. It should run in parallel with immediate backend hardening rather than block urgent remediation.

Subtasks:

1. Assign security ownership and launch decision criteria.
2. Produce threat model for escrow platform.
3. Specify funds ledger and escrow state machine.
4. Create authorization matrix for REST and Socket.IO.
5. Decide session, passkey, and admin step-up architecture.
6. Specify webhook security and provider adapter contracts.
7. Define secure build and supply-chain policy.
8. Make backend-core stack decision.
9. Create migration and operational runbooks.
