feat: add twitch tv login flow and auth state ui

cmd/parasocial/main.go

@@ -1,3 +1,6 @@
+// main.go is the executable entrypoint for the rewritten CLI.
+// It owns process-level concerns such as signal handling, exit codes,
+// and delegating the actual application startup to internal/app.
 package main
 
 import (
@@ -11,6 +14,7 @@ import (
 	"parasocial/internal/app"
 )
 
+// main sets up process cancellation and reports fatal startup errors to stderr.
 func main() {
 	ctx, stop := signal.NotifyContext(context.Background(), os.Interrupt, syscall.SIGTERM)
 	defer stop()