feat(gui): add ANSI escape sequence renderer with full panel integration

- new ansi_render module: SGR, cursor movement, erase, scroll
- integrate ANSI rendering into console panel output pipeline
- wire app_state, buffers, hex_view, and shortcuts for ANSI-aware display
- add test_ansi.py for manual ANSI sequence testing

crates/pipeview-gui/src/app.rs

@@ -1310,18 +1310,22 @@ fn render_send_panel(ui: &mut egui::Ui, manager: &SessionManager, tab: &mut Sess
     ui.add_space(3.0);
 
     let hint = match tab.send_mode {
-        SendMode::Text => "Enter text to send",
+        SendMode::Text => "Enter to send, Ctrl+Enter for newline",
         SendMode::Hex => "Enter hex bytes, e.g. 48 65 6C 6C 6F",
     };
     let response = ui.add(
         TextEdit::multiline(&mut tab.send_input)
             .desired_rows(6)
             .desired_width(f32::INFINITY)
+            .return_key(egui::KeyboardShortcut::new(
+                egui::Modifiers::COMMAND,
+                egui::Key::Enter,
+            ))
             .hint_text(hint),
     );
 
     let wants_submit = response.has_focus()
-        && ui.input(|input| input.key_pressed(egui::Key::Enter) && input.modifiers.command_only());
+        && ui.input(|input| input.key_pressed(egui::Key::Enter) && input.modifiers.is_none());
 
     let mut send_clicked = false;
     ui.horizontal(|ui| {