fix(v0.5.0): defaults and coupling issues from first walkthrough

- Configuration.cs: ShowTitleBar defaults to true so a fresh install
  shows the window header instead of leaving the user without a drag
  handle and hide button
- Configuration.cs: MaxLinesToRender default drops from 10000 to 5000
  to match the slider's intended ceiling and the previous user-tuned
  baseline
- ChatLogWindow.cs: 24h-clock checkbox now actually flips the format.
  The Bestand path passed null culture which on a German system
  locale always rendered 24h regardless of the toggle
- Appearance.cs + ChatLogWindow.cs + Popout.cs: when Hellion theme is
  enabled the global theme opacity drives the chat-window BgAlpha and
  the legacy WindowAlpha slider is disabled, so the two opacity
  controls no longer fight each other
- Appearance.cs: ticking UseHellionFont now flips FontsEnabled off so
  the two mutually-exclusive font stacks no longer appear active at
  the same time

ChatTwo/Ui/Popout.cs

@@ -70,8 +70,16 @@ internal class Popout : Window
 
         if (!ChatLogWindow.PopOutDocked[Idx])
         {
-            var alpha = Tab.IndependentOpacity ? Tab.Opacity : Plugin.Config.WindowAlpha;
-            BgAlpha = alpha / 100f;
+            if (Tab.IndependentOpacity)
+            {
+                BgAlpha = Tab.Opacity / 100f;
+            }
+            else
+            {
+                BgAlpha = Plugin.Config.HellionThemeEnabled
+                    ? Plugin.Config.HellionThemeWindowOpacity
+                    : Plugin.Config.WindowAlpha / 100f;
+            }
         }
     }