fix: 将所有emoji/Unicode特殊字符替换为ASCII安全字符

Windows cmd/PowerShell默认codepage下emoji显示为?号。
全局替换: 👋->移除, 💭->[Thinking], ⚙->*, ✓->[OK], ✗->[FAIL],
◆->>, ⚠->[!], ✅->[OK], •->|/-, →->>>, ✏️->[Edit]等。
❯保留（windows-vtp终端下正常显示）。

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

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

@@ -154,7 +154,7 @@ public class ReplSession {
                 handleInput(input, cmdContext);
             }
 
-            out.println(AnsiStyle.dim("\n  Goodbye! 👋\n"));
+            out.println(AnsiStyle.dim("\n  Goodbye!\n"));
         }
     }
 
@@ -174,8 +174,8 @@ public class ReplSession {
         out.println(AnsiStyle.dim("  Terminal: " + termInfo));
 
         if (isDumb) {
-            out.println(AnsiStyle.yellow("  ⚠ Dumb 终端模式：Tab补全和行编辑可能受限"));
-            out.println(AnsiStyle.yellow("    建议在 Windows Terminal / PowerShell / cmd.exe 中运行"));
+            out.println(AnsiStyle.yellow("  [!] Dumb terminal: Tab completion and line editing may be limited"));
+            out.println(AnsiStyle.yellow("      Run in Windows Terminal / PowerShell / cmd.exe for best experience"));
         } else {
             out.println(AnsiStyle.dim("  Tip: Tab to complete commands, ↑↓ to browse history, Ctrl+D to exit"));
         }
@@ -211,7 +211,7 @@ public class ReplSession {
             handleInput(input, cmdContext);
         }
 
-        out.println(AnsiStyle.dim("\n  Goodbye! 👋\n"));
+        out.println(AnsiStyle.dim("\n  Goodbye!\n"));
     }
 
     // ==================== 公共输入处理 ====================
@@ -237,7 +237,7 @@ public class ReplSession {
             out.println();
         } catch (Exception e) {
             spinner.stop();
-            out.println(AnsiStyle.red("\n  ✗ Error: " + e.getMessage()));
+            out.println(AnsiStyle.red("\n  [ERROR] " + e.getMessage()));
             log.error("Agent 循环异常", e);
             out.println();
         }