Add Customizable Output Filename Formatting

UI/Window/RenderConfigWindow.cs

@@ -135,6 +135,11 @@ internal static class RenderConfigWindow
     /// </summary>
     private static O5InputField? _outputDirInput;
 
+    /// <summary>
+    /// File name format template input. Bound to <c>GlobalSettings.Current.FileNameFormat</c>.
+    /// </summary>
+    private static O5InputField? _fileNameFormatInput;
+
     private static O5Dropdown<string>? _fileExtensionDropdown;
     private static O5InputField? _randomSeedInput;
     private static O5Toggle? _processAudioToggle;
@@ -698,6 +703,44 @@ internal static class RenderConfigWindow
             }
         );
 
+        // Filename format template: typing updates GlobalSettings.Current.FileNameFormat in memory only.
+        _fileNameFormatInput = CreateFullWidthInputField(
+            ctx, globalContent,
+            "ui.render_config.filename_format",
+            GlobalSettings.DefaultFileNameFormat,
+            GlobalSettings.EffectiveFileNameFormat,
+            "input_filename_format",
+            val =>
+            {
+                var trimmed = val?.Trim() ?? string.Empty;
+                if (string.IsNullOrWhiteSpace(trimmed) ||
+                    string.Equals(trimmed, GlobalSettings.DefaultFileNameFormat, StringComparison.Ordinal))
+                {
+                    GlobalSettings.Current.FileNameFormat = null;
+                }
+                else
+                {
+                    GlobalSettings.Current.FileNameFormat = trimmed;
+                }
+            }
+        );
+
+        var fnHint = CreateLabel(ctx, globalContent, "ui.render_config.filename_format_hint", 11f);
+        fnHint.color = new Color(ctx.Theme.TextDim.r, ctx.Theme.TextDim.g, ctx.Theme.TextDim.b, ctx.Theme.TextDim.a * 0.7f);
+
+        var (_, fnRight) = CreateTwoColumnPanel(globalContent);
+        CreateButton(
+            ctx, fnRight,
+            "ui.render_config.reset_filename_default",
+            "btn_reset_filename_format",
+            () =>
+            {
+                _fileNameFormatInput.Set(GlobalSettings.DefaultFileNameFormat);
+                GlobalSettings.Current.FileNameFormat = null;
+                GlobalSettings.Save();
+            }
+        );
+
         // ---------------------------------------------------------------------------------------------
         // Section 6: Advanced Settings card (RenderConfig.AdvancedConfig)
         //   File Extension | Random Seed
@@ -1045,6 +1088,7 @@ internal static class RenderConfigWindow
         _audioBitrateSlider?.Set(config.AudioConfig.AudioBitrate / 1000.0, false, noFilter: true);
 
         _outputDirInput?.Set(GlobalSettings.EffectiveOutputDirectory, false);
+        _fileNameFormatInput?.Set(GlobalSettings.EffectiveFileNameFormat, false);
 
         _fileExtensionDropdown?.Set(config.AdvancedConfig.FileExtension, false);
         _randomSeedInput?.Set(config.AdvancedConfig.RandomSeed?.ToString() ?? "", false);
@@ -1171,6 +1215,20 @@ internal static class RenderConfigWindow
             }
         }
 
+        if (_fileNameFormatInput != null)
+        {
+            var format = _fileNameFormatInput.Value.Trim();
+            if (string.IsNullOrWhiteSpace(format) ||
+                string.Equals(format, GlobalSettings.DefaultFileNameFormat, StringComparison.Ordinal))
+            {
+                GlobalSettings.Current.FileNameFormat = null;
+            }
+            else
+            {
+                GlobalSettings.Current.FileNameFormat = format;
+            }
+        }
+
         GlobalSettings.Save();
         SetWindowActive(false);