artifacts: move some of the artifacts code into its own module

src/main.rs

@@ -21,6 +21,7 @@ mod transcription;
 mod tts;
 mod prediction;
 mod audio;
+mod artifacts;
 
 // TODO: We should be able to delete entries from the conversation, or at least go back and edit something I said.
 // TODO: I want a "mark" command or keyboard shortcut, that inserts a marker into the log, so I know where to come back for the next speaking segment.