Thinking & tool call visibility settings for /copy and /export

[rektide]

• Use the current visibility settings for thinking and tool calls when doing /copy.
• For /export, there was an existing simple dialog box. Expand that with a new dialog option box, that includes two checkboxes for thinking & tool call visibility, defaulting to the current view settings.
  • It might be a better experience to remember the last setting, rather than following the UI every time? Or to remember the last setting for as long as the main visibility settings are the same, & reset if the main view visibility changes?

A possible fix for #1118 and #4609. Happy to implement suggestions/changes. Thanks all.