feat(record/amend): add support for detecting and adding untracked files

[claytonrcarter]

This updates git record and git amend to detect and optionally add new, untracked files when they are run.

• every invocation of git record and git amend updates a list of "known" untracked files in our internal sqlite db
• if a "new" untracked file is detected (ie it's on disk now, but isn't in the list from last run, in the db) then:
  • --untracked skip: (default) do nothing, as with current behavior
  • --untracked add: add all new files
  • --untracked prompt: prompts user for what to do with each file (add, skip, skip remaining, help)
• default behavior can be configured via branchless.record.untrackedFiles setting
• no untracked files are added/prompted if record/amend are invoked w/ staged changes
• a list of "known" (previously skipped) files is printed
• TODO probably want an --untracked off option, to disable all untracked file handling (eg if a repo often has lots and lots of untracked files (for reasons?) then this could be obnoxious)