Implements _cdp_get_origins() method to capture localStorage and sessionStorage
using cdp-use's typed DOMStorage client. This enables proper session
persistence for applications that store authentication tokens in browser storage
rather than cookies.

- Adds _cdp_get_origins() to enumerate all frames and extract unique origins
- Uses cdp-use's DOMStorage.getDOMStorageItems to retrieve localStorage/sessionStorage
- Updates _cdp_get_storage_state() to include origins in storage state
- Handles errors gracefully with debug logging for individual storage failures
- Uses try-finally to ensure DOMStorage is properly disabled even on errors
- Encapsulates storage extraction logic in helper functions for clarity