SingleFile CLI 2.18.2

CLI fixes and improvements

• The cookies, the extra HTTP headers and the proxy settings passed on the command line no longer reach the page. They were part of the options given to the capture script, and the user-script event handed that object to the page.
• --user-script-enabled is no longer on by default. The event API is enabled when --browser-script is set, or when the option is passed explicitly.
• Update single-file-core to 1.6.29: the options are no longer sent to child frames, the user-script events no longer expose the destination and credential options, the matched <source> of a <picture> keeps its size on the saved image, and the serialised adopted stylesheets are cached for one capture only.

Co-authored by Claude (Claude Code)