chore: bump version to 3.0.0-alpha.20

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: john-zhh

cmd/root.go

@@ -32,7 +32,7 @@ import (
 // stdinReader is the reader used for interactive prompts. Tests can replace it.
 var stdinReader io.Reader = os.Stdin
 
-var Version = "3.0.0-alpha.19"
+var Version = "3.0.0-alpha.20"
 
 var updateChecker *update.Checker