Refactored the checkResponseError function to handle Axios errors more effectively. Now, if an error response contains either an "error" or a "detail" property, it will throw an Error with the corresponding message. This change improves the error reporting and makes the code more robust.

Closes cashubtc#123

The `isObj` function in the `utils.ts` file has been updated to provide more accurate type checking. Instead of simply checking if the value is an object, it now checks if the value is an object with a string key and unknown value. This change improves the reliability of type checking in the codebase, because in TypeScript, null is considered an object, which can lead to unexpected behavior.

- added explainer comments
- made check response error more concise

changes:
- Exported `splitAmount`, `getDefaultAmountPreference`, `bytesToNumber`, `hexToNumber`, and `bigIntStringify` functions.
- Added JSDoc comments for new functions: `isPowerOfTwo`, `getPreference`, and other utility functions.
- Improved code readability by adding line breaks and indentation.

Added try-catch block to handle errors when getting preferences. Log error message if an exception occurs during preference retrieval.

- Refactored code to separate prefix removal logic into a new function. Updated getDecodedToken to utilize this function for removing prefixes before handling tokens.

and invoice decoding functions. Add type annotations and cleanup code.

The isPowerOfTwo function in utils.ts was updated to include type annotations for better type safety. The return value now explicitly states the boolean type.

The function bigIntStringify now returns a stringified value using JSON.stringify for non-bigint values.