style: make verbose fields private

Co-authored-by: aider (openai/andrew/openrouter/qwen/qwen3-coder) <aider@aider.chat>

src/args.rs

@@ -129,7 +129,7 @@ pub struct OptionsArgs {
 
     #[arg(short, long, action = clap::ArgAction::Count, conflicts_with("quiet"))]
     #[arg(help("Increase message verbosity, can be given more than once"))]
-    pub verbose: u8,
+    pub(crate) verbose: u8,
 
     #[arg(short, long)]
     #[arg(help("Do not show any messages"))]