feat: add Show script trace in terminal setting

Settings -> Terminal gains a 'Show script trace in terminal' checkbox
(AppSettings.ShowScriptTrace, default on). When off, TTL trace lines
([wait] progress, sent-command echo, errors) are no longer drawn in
the terminal. dispstr moves to a dedicated Display event and always
shows, since it is the script explicitly printing something.

Trace was already display-only (never written to session logs, the AI
serial bridge, or the device) - docs now state this explicitly.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

src/ETTerms/App/AboutView.cs

@@ -189,7 +189,7 @@ public sealed class AboutView : UserControl
             "New Settings → Highlight page: add your own keywords (like ERROR or FAIL) and they light up in red wherever they appear.",
             "When a keyword shows up in a tab you're not looking at, that tab's dot turns red so you don't miss it.",
             "TTL scripting grew from ~15 commands to 90+, matching Tera Term macros: loops (for / do / until), goto and subroutines, waitln / waitregex with regex capture, string and file operations, input dialogs, and serial line control (sendbreak, setbaud).",
-            "Scripts now show their progress in gray right inside the terminal, so you can watch what they're doing.",
+            "Scripts now show their progress in gray right inside the terminal — display only, never written to session logs; turn it off in Settings → Terminal (Show script trace) if you want a clean screen.",
             "See the full command table with examples in docs/ttl-script-reference.md.",
         ]),
         new("0.4.0", new DateOnly(2026, 7, 2), "Performance & stability overhaul",

src/ETTerms/App/SettingsView.cs

@@ -94,6 +94,14 @@ public sealed class SettingsView : UserControl
         flow.Controls.Add(MakeRow("Scrollback Lines", scrollback));
         flow.Controls.Add(MakeRow("Color Scheme", scheme));
         flow.Controls.Add(MakeRow("Default Newline", newline));
+
+        var scriptTrace = new CheckBox
+        {
+            Text = "Show script trace in terminal  ([wait] / sent commands / errors in gray; dispstr always shows)",
+            Checked = s.ShowScriptTrace, AutoSize = true,
+            ForeColor = Theme.Text, Font = Theme.UiFont, Margin = new Padding(0, 6, 0, 0)
+        };
+        flow.Controls.Add(scriptTrace);
         flow.Controls.Add(MakeSpacer(16));
 
         // Shell settings
@@ -161,6 +169,7 @@ public sealed class SettingsView : UserControl
             s.ScrollbackLines = (int)scrollback.Value;
             s.ColorScheme = scheme.Text;
             s.DefaultNewLine = newline.Text;
+            s.ShowScriptTrace = scriptTrace.Checked;
             s.ShellType = shellType.Text;
             s.ShellStartupDir = shellDir.Text;
             s.Save();

src/ETTerms/Infrastructure/AppSettings.cs

@@ -22,6 +22,9 @@ public sealed class AppSettings
     public int ScrollbackLines { get; set; } = 5000;
     public string DefaultNewLine { get; set; } = "\\r\\n";
     public string ColorScheme { get; set; } = "Dark";
+    /// <summary>TTL 腳本執行時，[wait] / >> 送出回顯 / 錯誤等 trace 是否以灰色顯示在終端機
+    /// （只影響畫面；本來就不會寫進側錄 log。dispstr 一律顯示，不受此開關影響）。</summary>
+    public bool ShowScriptTrace { get; set; } = true;
 
     // ── Shell ──
     public string ShellType { get; set; } = "PowerShell";       // PowerShell, Bash, Cmd

src/ETTerms/Scripting/ScriptRunner.cs

@@ -14,9 +14,12 @@ public sealed class ScriptRunner
     /// <summary>(檔名, 行號, 指令) 進度。</summary>
     public event Action<string, int, string>? StatusChanged;
 
-    /// <summary>輸出訊息（log / 提示 / 錯誤）。</summary>
+    /// <summary>trace 訊息（[wait] 進度 / >> 送出回顯 / 錯誤）；顯示與否由 UI 依設定決定。</summary>
     public event Action<string>? Output;
 
+    /// <summary>dispstr 的顯示輸出（一律顯示）。</summary>
+    public event Action<string>? Display;
+
     /// <summary>結束：(成功, 訊息)。</summary>
     public event Action<bool, string>? Finished;
 
@@ -37,6 +40,7 @@ public sealed class ScriptRunner
         var interp = new TTLInterpreter(channel, sync, memberLabel);
         interp.StatusChanged += (f, l, c) => StatusChanged?.Invoke(f, l, c);
         interp.Output += m => Output?.Invoke(m);
+        interp.Display += m => Display?.Invoke(m);
         _interp = interp;
 
         try

src/ETTerms/Scripting/TTLInterpreter.cs

@@ -56,9 +56,13 @@ public sealed class TTLInterpreter : IDisposable
     /// <summary>(檔名, 行號, 當前指令) 進度更新。</summary>
     public event Action<string, int, string>? StatusChanged;
 
-    /// <summary>輸出訊息（log / 提示 / 錯誤 / dispstr），供 UI 顯示。</summary>
+    /// <summary>trace 訊息（[wait] 進度 / >> 送出回顯 / 錯誤），供 UI 顯示；
+    /// 可由 Settings 的 Show script trace 開關關閉顯示。</summary>
     public event Action<string>? Output;
 
+    /// <summary>dispstr 的顯示輸出：腳本明確要顯示的內容，一律顯示（不受 trace 開關影響）。</summary>
+    public event Action<string>? Display;
+
     public TTLInterpreter(ISessionChannel channel, GroupSyncContext? groupSync = null, string memberLabel = "")
     {
         _channel = channel ?? throw new ArgumentNullException(nameof(channel));
@@ -1065,7 +1069,7 @@ public sealed class TTLInterpreter : IDisposable
         var t = TokenizeArgs(args);
         var sb = new StringBuilder();
         foreach (var tok in t) sb.Append(ValS(tok));
-        Output?.Invoke(sb.ToString());
+        Display?.Invoke(sb.ToString());
     }
 
     private void SendFile(string args)

src/ETTerms/Sessions/SessionPage.cs

@@ -100,8 +100,15 @@ public sealed class SessionPage : UserControl
 
         _runner.StatusChanged += (_, line, cmd) => Ui(() => _status.Text = $"line {line}: {Trunc(cmd)}");
         _runner.Finished += (_, msg) => Ui(() => { _status.Text = msg; SetRunning(false); });
-        // 腳本輸出（dispstr / [wait] 進度 / 錯誤）以灰色 echo 到終端機，執行過程看得見
-        _runner.Output += m => Ui(() =>
+        // 腳本 trace（[wait] 進度 / >> 送出回顯 / 錯誤）以灰色 echo 到終端機；
+        // 可由 Settings → Terminal 的 Show script trace 關閉。只影響畫面，不會進側錄 log。
+        _runner.Output += m =>
+        {
+            if (!AppSettings.Instance.ShowScriptTrace) return;
+            Ui(() => _term.Feed(System.Text.Encoding.UTF8.GetBytes($"\x1b[90m{m}\x1b[0m\r\n")));
+        };
+        // dispstr 是腳本明確要顯示的內容，一律顯示（不受開關影響）
+        _runner.Display += m => Ui(() =>
             _term.Feed(System.Text.Encoding.UTF8.GetBytes($"\x1b[90m{m}\x1b[0m\r\n")));
     }