refactor: update PTY fallback handling for consistent terminal output

Author: vinhnx

vtcode-tui/src/core_tui/session/message_renderer.rs

@@ -53,8 +53,8 @@ pub(super) fn render_message_spans(
         // Render PTY content with a subdued foreground color instead of the
         // terminal DIM modifier, which can be too faint on many terminals.
         // Segments that carry their own ANSI color keep it; uncolored segments
-        // get the theme's pty_body color for consistent, readable contrast.
-        let pty_fallback = theme.pty_body.or(theme.foreground);
+        // use the configured PTY fallback chain from session styling.
+        let pty_fallback = text_fallback_fn(InlineMessageKind::Pty).or(theme.foreground);
         for segment in &line.segments {
             let style = ratatui_pty_style_from_inline(&segment.style, pty_fallback);
             spans.push(Span::styled(segment.text.clone(), style));

vtcode-tui/src/core_tui/session/reflow/blocks.rs

@@ -401,9 +401,11 @@ impl Session {
         }
 
         // Render body content - strip ANSI codes to ensure plain text output.
-        // Use the theme's pty_body color as fallback instead of terminal DIM
-        // for consistent, readable contrast across terminals.
-        let pty_fallback = self.theme.pty_body.or(self.theme.foreground);
+        // Use the session PTY fallback chain (pty_body -> tool_body -> foreground)
+        // and apply a consistent dimmed style for terminal output.
+        let pty_fallback = self
+            .text_fallback(InlineMessageKind::Pty)
+            .or(self.theme.foreground);
         let mut body_spans = Vec::new();
         for segment in &line.segments {
             let stripped_text = render::strip_ansi_codes(&segment.text);