enhance: improve assistant message rendering and console patching

- Split multi-line assistant messages into separate rendered lines
- Add streaming cursor (▌) indicator for in-progress responses
- Add patchConsole() to intercept System.out/err during TUI mode
- Handle empty assistant message edge case

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

src/main/java/com/claudecode/tui/ClaudeCodeComponent.java

@@ -225,10 +225,42 @@ public class ClaudeCodeComponent extends Component<ClaudeCodeComponent.TuiState>
 
             case AssistantMsg m -> {
                 List<Renderable> lines = new ArrayList<>();
+                String text = m.text();
+                if (text == null || text.isEmpty()) {
+                    if (m.streaming()) {
                         lines.add(Text.of(
                                 Text.of("● ").color(Color.BRIGHT_CYAN),
-                        Text.of(m.streaming() ? m.text() + "▌" : m.text()).color(Color.WHITE)
+                                Text.of("▌").color(Color.BRIGHT_CYAN)
                         ));
+                    }
+                    yield lines;
+                }
+                // 将多行文本拆分为单独的行
+                String[] textLines = text.split("\n", -1);
+                for (int i = 0; i < textLines.length; i++) {
+                    String line = textLines[i];
+                    if (i == 0) {
+                        // 首行带 ● 前缀
+                        String displayLine = line;
+                        if (m.streaming() && i == textLines.length - 1) {
+                            displayLine += "▌";
+                        }
+                        lines.add(Text.of(
+                                Text.of("● ").color(Color.BRIGHT_CYAN),
+                                Text.of(displayLine).color(Color.WHITE)
+                        ));
+                    } else {
+                        // 续行缩进对齐
+                        String displayLine = line;
+                        if (m.streaming() && i == textLines.length - 1) {
+                            displayLine += "▌";
+                        }
+                        lines.add(Text.of(
+                                Text.of("  ").dimmed(),
+                                Text.of(displayLine).color(Color.WHITE)
+                        ));
+                    }
+                }
                 yield lines;
             }
 

src/main/java/com/claudecode/tui/JinkReplSession.java

@@ -96,6 +96,9 @@ public class JinkReplSession {
         // 启动 jink 渲染
         inkApp = Ink.render(component);
 
+        // 拦截 System.out/err，防止日志干扰 TUI
+        inkApp.patchConsole();
+
         // 阻塞等待退出
         inkApp.waitUntilExit();