Fix stale cmd/ scripts, export LoginWithChromedp, clean up vet warnings

Update 5 cmd/ test utilities that referenced APIs that drifted after
bridge refactors (NewBrowserAuthManager, bridge.NewConfig, changed
function signatures). Rewrite test-kosmi and test-native to use
NewGraphQLWSClient directly. Export LoginWithChromedp for use by cmd
scripts. Fix redundant-newline vet warnings across 5 cmd/ files.
Remove unreachable code and replace deprecated ioutil calls in
bridge/helper/lottie_convert.go.

Made-with: Cursor

cmd/test-image-upload/main.go

@@ -9,11 +9,11 @@ import (
 )
 
 func main() {
-	fmt.Println("=== Kosmi Image Upload Test ===\n")
+	fmt.Println("=== Kosmi Image Upload Test ===")
 
 	// Test 1: Generate a room code image
 	fmt.Println("1. Generating room code image for 'TEST'...")
-	imageData, err := jackbox.GenerateRoomCodeImage("TEST")
+	imageData, err := jackbox.GenerateRoomCodeImage("TEST", "Test Game")
 	if err != nil {
 		log.Fatalf("Failed to generate image: %v", err)
 	}