* refactor(cdk-lnbits): migrate to LNbits v1 websocket API and remove webhook support
- Remove webhook-based payment notifications in favor of v1 websocket API
- Add explicit documentation that only LNbits v1 API is supported
- Remove webhook_url parameter and related router setup code
- Simplify payment status handling by removing pending status logic
- Switch to local lnbits-rs dependency for development
- Remove unused axum dependency and clean up imports
- Update configuration documentation and examples
* refactor(cdk-lnbits): extract payment processing logic into helper methods
Improve code readability by separating message processing, payment response
creation, and payment hash decoding into dedicated methods. This reduces
complexity in the main payment waiting loop while maintaining identical
functionality
* chore: bump lnbits-rs
