- Move all file reading and content-inlining logic into a new
'addFile' function in its own 'add.go' file.
- The main function now calls this to parse a log file and then
appends the returned chats to the main session.
- This improves separation of concerns and makes the main loop cleaner.
- Update main.go and doPlayback.go to be compatible with the
refactored 'Chat -> Entries' protobuf message format.
- Remove the now-obsolete format_rich_log.go file.
- The application now compiles successfully against the new chatpb library.