fix: add missing FromStr trait import

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

src/args.rs

@@ -1,4 +1,5 @@
 use std::path::PathBuf;
+use std::str::FromStr;
 
 use clap::*;
 use anyhow::{Error, anyhow};