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/Configuration.cs

@@ -147,7 +147,7 @@ public class Configuration : IPluginConfiguration
     public LanguageOverride LanguageOverride = LanguageOverride.None;
     public bool CanMove = true;
     public bool CanResize = true;
-    public bool ShowTitleBar;
+    public bool ShowTitleBar = true;
     public bool ShowPopOutTitleBar = true;
     public bool DatabaseBattleMessages;
     public bool LoadPreviousSession;
@@ -157,7 +157,7 @@ public class Configuration : IPluginConfiguration
     public bool CollapseKeepUniqueLinks;
     public bool PlaySounds = true;
     public bool KeepInputFocus = true;
-    public int MaxLinesToRender = 10_000; // 1-10000
+    public int MaxLinesToRender = 5_000; // 1-10000
     public bool Use24HourClock;
 
     public bool ShowEmotes = true;