* refactor(keychain): improve error handling and consistency across platforms
- Change platformGet to return error instead of empty string
- Add proper error wrapping for keychain operations
- Make master key creation conditional in getMasterKey
- Improve error messages and handling for keychain access
- Update dependent code to handle new error returns
* docs(keychain): improve function documentation and error message
Add detailed doc comments for all platform-specific keychain functions to clarify their purpose and behavior. Also enhance the error hint message to include a suggestion for reconfiguring the CLI when keychain access fails.
* refactor(keychain): reorder operations in platformGet for better error handling
Check for file existence before attempting to read and get master key
* fix(keychain): improve error handling and consistency across platforms.
* fix(keychain): handle corrupted master key case
* fix(keychain): handle I/O errors when reading master key
