feat: Bank Sync Connector Architecture (Issue #75)

[Abu1982]

Summary

Implements a pluggable bank connector architecture as requested in Issue #75.

Changes

1. Bank Connector Interface (�pp/services/bank_connectors/init.py):

   • Abstract BankConnector base class with interface methods
   • BankAccount and Transaction dataclasses
   • Factory function for connector registration

2. Mock Connector (�pp/services/bank_connectors/mock.py):

   • Full mock implementation for testing/development
   • Returns sample accounts and transactions

3. API Routes (�pp/routes/bank_connector.py):

   • GET /bank/accounts - List connected accounts
   • GET /bank/accounts//transactions - Get transactions
   • POST /bank/accounts//refresh - Refresh account balance
   • GET /bank/connectors - List available connector types
   • POST /bank/test-connection - Test connection

Acceptance Criteria Met

• ✅ Connector interface
• ✅ Import & refresh support
• ✅ Mock connector included

Testing

The mock connector provides:

• 3 mock accounts (checking, savings, credit)
• Sample transactions for the last 30 days

To test locally:
`�ash

With mock connector (no API key needed)

curl http://localhost:5000/bank/accounts?connector_type=mock
`

Closes #75