fix: CLI交互优化 - 流式缩进+输入框横线+日志降噪

- 流式输出: ● 标识与文本同行，续行4空格缩进对齐
- 输入框: 上下横线(─)分隔输入区域，宽度自适应终端
- 日志: 工具异常日志降为debug级别，避免终端输出stack trace

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

src/main/java/com/claudecode/repl/ReplSession.java

@@ -192,9 +192,17 @@ public class ReplSession {
                 statusLine.enable(providerInfo.model(), agentLoop.getTokenTracker());
             }
 
+            // 输入框横线宽度
+            int termWidth = terminal.getWidth();
+            int lineWidth = termWidth > 10 ? termWidth - 2 : 78;
+            String inputLine = AnsiStyle.DIM + "─".repeat(lineWidth) + AnsiStyle.RESET;
+
             CommandContext cmdContext = new CommandContext(agentLoop, toolRegistry, commandRegistry, out, () -> running = false);
 
             while (running) {
+                // 输入框上横线
+                out.println(inputLine);
+
                 String input;
                 try {
                     input = reader.readLine(prompt).strip();
@@ -206,6 +214,9 @@ public class ReplSession {
                     break;
                 }
 
+                // 输入框下横线
+                out.println(inputLine);
+
                 if (input.isEmpty()) {
                     continue;
                 }
@@ -317,12 +328,25 @@ public class ReplSession {
 
             long startTime = System.currentTimeMillis();
 
-            // AI 回复前的 ● 标识
-            out.println(AnsiStyle.BRIGHT_CYAN + "  ● " + AnsiStyle.RESET);
+            // AI 回复前的 ● 标识（不换行，后续流式文本紧跟其后）
+            out.print(AnsiStyle.BRIGHT_CYAN + "  ● " + AnsiStyle.RESET);
 
-            // 流式回调：逐 token 输出到终端
+            // 流式回调：逐 token 输出到终端，自动在每行开头加缩进
+            final boolean[] isNewLine = {false}; // 跟踪是否刚输出换行符
             String response = agentLoop.runStreaming(input, token -> {
-                out.print(token);
+                for (int i = 0; i < token.length(); i++) {
+                    char c = token.charAt(i);
+                    if (c == '\n') {
+                        out.println();
+                        isNewLine[0] = true;
+                    } else {
+                        if (isNewLine[0]) {
+                            out.print("    "); // 续行缩进（与 ● 后文本对齐）
+                            isNewLine[0] = false;
+                        }
+                        out.print(c);
+                    }
+                }
                 out.flush();
             });
 

src/main/java/com/claudecode/tool/impl/AgentTool.java

@@ -92,7 +92,7 @@ public class AgentTool implements Tool {
             log.info("Sub-agent completed, result length: {} chars", result.length());
             return result;
         } catch (Exception e) {
-            log.error("Sub-agent execution failed", e);
+            log.debug("Sub-agent execution failed", e);
             return "Error: Sub-agent failed: " + e.getMessage();
         }
     }

src/main/java/com/claudecode/tool/impl/AskUserQuestionTool.java

@@ -119,7 +119,7 @@ public class AskUserQuestionTool implements Tool {
             return "User response: " + userResponse;
 
         } catch (Exception e) {
-            log.error("Failed to get user input", e);
+            log.debug("Failed to get user input", e);
             return "Error: Failed to get user input - " + e.getMessage();
         }
     }

src/main/java/com/claudecode/tool/impl/WebSearchTool.java

@@ -92,7 +92,7 @@ public class WebSearchTool implements Tool {
             String html = fetchSearchPage(query);
             return parseResults(html, maxResults);
         } catch (Exception e) {
-            log.error("Search failed: query={}", query, e);
+            log.debug("Search failed: query={}", query, e);
             return "Error: Search failed - " + e.getMessage();
         }
     }