feat(window): restore the title-bar, hide-button, and 24-hour-clock toggles

Re-wires four 1.5.6 settings that survived the v1.6.0 rewrite as dormant config
fields but lost their UI + consumers:
- ShowTitleBar / ShowPopOutTitleBar: gate ImGuiWindowFlags.NoTitleBar on the main
  window (ResolveFlags) and pop-out windows (new PreDraw). Inverted logic matches
  1.5.6 (flag set only when the toggle is off).
- ShowHideButton: gate the input-bar hide button on the toggle.
- Use24HourClock: add the toggle (MessageList already consumes the field).
New 'Window style' section in WindowTab; Use24HourClock in ChatTab display modes.
MainWindowFlagsStep extended with the NoTitleBar fresh-base contract.

HellionChat/Ui/Components/InputBar.cs

@@ -540,15 +540,21 @@ internal sealed class InputBar
                     ImGui.SetTooltip("Settings");
             }
 
-            ImGui.SameLine();
-            var hidden = Plugin.Config.HideChat;
-            var visIcon = hidden ? FontAwesomeIcon.EyeSlash : FontAwesomeIcon.Eye;
-            if (ImGui.Button(visIcon.ToIconString()))
-                Plugin.Config.HideChat = !hidden;
-            if (ImGui.IsItemHovered())
+            // Hide button gated on ShowHideButton (1.5.6 parity). It is the last
+            // button in the row, so skipping it (with its leading SameLine) leaves
+            // no dangling SameLine. Shared by main + pop-out InputBars.
+            if (Plugin.Config.ShowHideButton)
             {
-                using (ImRaii.DefaultFont())
-                    ImGui.SetTooltip(hidden ? "Unhide chat" : "Hide chat");
+                ImGui.SameLine();
+                var hidden = Plugin.Config.HideChat;
+                var visIcon = hidden ? FontAwesomeIcon.EyeSlash : FontAwesomeIcon.Eye;
+                if (ImGui.Button(visIcon.ToIconString()))
+                    Plugin.Config.HideChat = !hidden;
+                if (ImGui.IsItemHovered())
+                {
+                    using (ImRaii.DefaultFont())
+                        ImGui.SetTooltip(hidden ? "Unhide chat" : "Hide chat");
+                }
             }
         }
     }