fix: Remove unused imports from various modules

Co-authored-by: aider (openai/andrew/openrouter/deepseek/deepseek-chat-v3.1) <aider@aider.chat>

src/modes/common.rs

@@ -7,7 +7,6 @@ use log::debug;
 use regex::Regex;
 use std::collections::HashMap;
 use std::env;
-use std::io::IsTerminal;
 use std::str::FromStr;
 use strum::IntoEnumIterator;
 use termsize;