Adds a new module for tracking user expenses.
The module includes:
- Configuration settings for the LNbits API endpoint and timeouts.
- An ExpensesAPI service for fetching accounts and submitting expense entries.
- A UI component for adding expenses, including account selection and form input.
- Dependency injection for the ExpensesAPI service.
This allows users to submit expense entries with account selection and reference data, which will be linked to their wallet.
