chore(style): remove unused helper functions

Remove RenderSuccess, RenderWarning, RenderError, and RenderInfo
functions that were never used. The codebase uses style.SuccessPrefix
and style.Success.Render() directly instead.

Closes gt-nz6t.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

internal/style/style.go

@@ -43,23 +43,3 @@ var (
 	// ArrowPrefix for action indicators
 	ArrowPrefix = Info.Render("→")
 )
-
-// RenderSuccess formats a success message
-func RenderSuccess(msg string) string {
-	return SuccessPrefix + " " + msg
-}
-
-// RenderWarning formats a warning message
-func RenderWarning(msg string) string {
-	return WarningPrefix + " " + msg
-}
-
-// RenderError formats an error message
-func RenderError(msg string) string {
-	return ErrorPrefix + " " + msg
-}
-
-// RenderInfo formats an info message with arrow
-func RenderInfo(msg string) string {
-	return ArrowPrefix + " " + msg
-}