feat(ui): separate opacity for focused and unfocused chat window

HellionChat/Ui/ChatLogWindow.cs

@@ -709,7 +709,15 @@ public sealed class ChatLogWindow : Window
         // Window-Deckkraft eingestellt hat, hat dieses Per-Window-Override
         // Vorrang über unseren Slider — wir dokumentieren das im HelpMarker.
         if (LastViewport == ImGuiHelpers.MainViewport.Handle && !WasDocked)
-            BgAlpha = Plugin.Config.WindowOpacity;
+        {
+            // UI-12: focus-dependent opacity. PreOpenCheck runs before Begin();
+            // Window.IsFocused holds last frame's RootAndChildWindows focus, set
+            // by Dalamud's WindowHost after Begin(). One-frame latency is
+            // accepted.
+            BgAlpha = IsFocused
+                ? Plugin.Config.WindowOpacity
+                : Plugin.Config.WindowOpacityInactive;
+        }
 
         LastViewport = ImGui.GetWindowViewport().Handle;
         WasDocked = ImGui.IsWindowDocked();

HellionChat/Ui/SettingsTabs/ThemeAndLayout.cs

@@ -296,6 +296,24 @@ internal sealed class ThemeAndLayout : ISettingsTab
             }
             ImGuiUtil.HelpMarker(HellionStrings.Settings_ThemeAndLayout_WindowOpacity_Description);
 
+            // UI-12: inactive-window opacity, same 50-100% range and clamp.
+            var inactiveOpacityPercent = Mutable.WindowOpacityInactive * 100f;
+            if (
+                ImGuiUtil.DragFloatVertical(
+                    HellionStrings.Settings_ThemeAndLayout_WindowOpacityInactive_Name,
+                    ref inactiveOpacityPercent,
+                    .25f,
+                    50f,
+                    100f,
+                    $"{inactiveOpacityPercent:N0}%%",
+                    ImGuiSliderFlags.AlwaysClamp
+                )
+            )
+            {
+                Mutable.WindowOpacityInactive = inactiveOpacityPercent / 100f;
+            }
+            ImGuiUtil.HelpMarker(HellionStrings.Settings_ThemeAndLayout_WindowOpacityInactive_Description);
+
             ImGui.Spacing();
             ImGui.Separator();
             ImGui.Spacing();