feat: fzf-powered picker for list commands

[notnmeyer]

adds a --pick flag to auth list, transactional list, campaigns list, and lists list. --pick will launch fzf and make the content filterable and allows identifiers to be copied.

• auth list --pick: little bit of a special case, switches to the selected team like auth use blah would.
• transaction list --pick: copies transactional id
• lists list --pick: copies mailing list id
• campaigns list --pick:
  • copies campaign id
  • <opt|alt+enter> copies email message id

requires fzf is installed. if fzf isnt found,

➜ loops auth list --pick

   ERROR

  --Pick requires fzf to be installed and on PATH.