fix: correct misleading SIGPIPE comment (#776)

The comment said "Ignore SIGPIPE" but the code actually resets SIGPIPE
to SIG_DFL (default behavior = process termination), not SIG_IGN (ignore).
Updated the comment to accurately describe what the code does and why.

Co-authored-by: hyunjinee <leehj0110@kakao.com>
Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

cli/src/main.rs

@@ -164,7 +164,8 @@ fn run_session(args: &[String], session: &str, json_mode: bool) {
 }
 
 fn main() {
-    // Ignore SIGPIPE to prevent panic when piping to head/tail
+    // Rust ignores SIGPIPE by default, causing println! to panic on broken pipes.
+    // Reset to SIG_DFL so the OS terminates the process cleanly instead.
     #[cfg(unix)]
     unsafe {
         libc::signal(libc::SIGPIPE, libc::SIG_DFL);