fix(tui): perbaiki rendering multi-baris pada pesan Tool

Konten Tool sebelumnya didorong sebagai satu Span tanpa split newline,
sehingga output tool multi-baris (stdout bash, hasil grep, diff)
tampil sebagai karakter \n literal alih-alih baris terpisah. Sekarang
mengikuti pola render_markdown + split_spans_into_lines yang sama
dengan role lain.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

src/view/chat.rs

@@ -117,18 +117,40 @@ pub fn draw_chat(frame: &mut Frame, area: Rect, state: &crate::app::state::rest:
         let is_last = std::ptr::eq(msg, messages.last().unwrap());
 
         // Tool messages render as a dim sub-line attached to whatever came
-        // before — no header, no speaker-change bookkeeping.
+        // before — no header, no speaker-change bookkeeping. Content is run
+        // through the same render_markdown + split_spans_into_lines pipeline
+        // as every other role so multi-line tool output (bash stdout, grep
+        // matches, diffs) becomes real wrapped `Line`s instead of a literal
+        // `\n` inside one Span; every rendered span is then re-styled dim
+        // italic to preserve the original single-line look.
         if msg.role == Role::Tool {
             let content = if msg.content.trim().is_empty() {
                 "(tool execution)".to_string()
             } else {
                 msg.content.clone()
             };
-            display_lines.push(Line::from(vec![
+            let dim = Style::default().fg(Theme::TEXT_DIM);
+            let dim_italic = dim.add_modifier(Modifier::ITALIC);
+
+            let content_spans = super::markdown::render_markdown(&content, content_width);
+            let content_lines = split_spans_into_lines(content_spans);
+            let mut lines_iter = content_lines.into_iter();
+
+            let first_spans = lines_iter.next().map_or_else(Vec::new, |line| {
+                line.spans.into_iter().map(|s| Span::styled(s.content, dim_italic)).collect()
+            });
+            let mut spans = vec![
                 Span::raw(" ".repeat(PREFIX_WIDTH)),
-                Span::styled("↳ ", Style::default().fg(Theme::TEXT_DIM)),
-                Span::styled(content, Style::default().fg(Theme::TEXT_DIM).add_modifier(Modifier::ITALIC)),
-            ]));
+                Span::styled("↳ ", dim),
+            ];
+            spans.extend(first_spans);
+            display_lines.push(Line::from(spans));
+
+            for line in lines_iter {
+                let mut spans = vec![Span::raw(" ".repeat(PREFIX_WIDTH))];
+                spans.extend(line.spans.into_iter().map(|s| Span::styled(s.content, dim_italic)));
+                display_lines.push(Line::from(spans));
+            }
             continue;
         }