Wire KYC/compliance checks into transaction flow, add audit logging, and dispute UI

- Add kyc_client.py with fail-closed pattern for bank-grade KYC verification
- Add compliance_client.py with AML/sanctions screening before transactions
- Add audit_client.py in common module for audit logging across services
- Wire KYC check (step 1) before transaction creation in routes.py
- Wire compliance check (step 2) before transaction creation in routes.py
- Add audit logging after transaction creation (fire-and-forget)
- Add Disputes page to PWA with create/view dispute functionality
- Add disputes route to PWA App.tsx

This ensures no orphaned services - KYC, compliance, audit, and dispute services
are now properly integrated into the transaction flow and UI.

Co-Authored-By: Patrick Munis <pmunis@gmail.com>

Author: devin-ai-integration[bot]