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-session/main.go

@@ -68,7 +68,7 @@ func main() {
 	fmt.Println("✅ WebSocket connected!")
 
 	// Step 3: Listen for messages
-	fmt.Println("\n👂 Listening for messages (press Ctrl+C to exit)...\n")
+	fmt.Println("\n👂 Listening for messages (press Ctrl+C to exit)...")
 	
 	messageCount := 0
 	for {