feat: add ellipsis when truncating strings and only apply max_len for terminal output

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

src/modes/common.rs

@@ -46,7 +46,30 @@ pub fn string_column(s: String, column_width: usize) -> String {
     if column_width > 0 {
         match s.char_indices().nth(column_width) {
             None => s.to_string(),
-            Some((idx, _)) => s[..idx].to_string(),
+            Some((idx, _)) => {
+                if column_width > 1 {
+                    // Find where to cut to fit the ellipsis
+                    let mut cut_idx = idx;
+                    // We need to make room for the ellipsis character
+                    // Find the character boundary before the cut index
+                    for i in (0..idx).rev() {
+                        if s.is_char_boundary(i) {
+                            if idx - i >= 3 { // Make sure we have enough room
+                                cut_idx = i;
+                                break;
+                            }
+                        }
+                    }
+                    // If we can't find a good place, just truncate without ellipsis
+                    if cut_idx >= 3 {
+                        format!("{}…", &s[..cut_idx - 1])
+                    } else {
+                        s[..idx].to_string()
+                    }
+                } else {
+                    s[..idx].to_string()
+                }
+            }
         }
     } else {
         s.to_string()