Show estimate before the review and statistics after the review

[sttlr]

It would be great to show the estimate before the review:

• number of files to review
• estimated number of completion requests
• $ estimate (input token count / inference price)
• ...

It would also be great to show the statistics after the review:

• number of files reviewed
• percent of files with issues
• number of completion requests made
• number of input/output tokens generated
• average file review time
• $ spent
• $ per issue discovered
• ....