chore(config): align defaults with maintainer's live config

Three real-world adjustments to the default config that ships with a
fresh install:

- HellionThemeWindowOpacity 0.92 -> 0.5 so a fresh install lands at
  the more glass-like default the maintainer uses daily
- Use24HourClock false -> true to match a German / European locale.
  Works correctly thanks to the v0.5.1 strict-format fix that uses
  CultureInfo.InvariantCulture instead of the host culture
- HellionParty preset Channel: InputChannel.Party -> null. Auto-
  routing /party into a tab that also collects /alliance and /pvpteam
  surprises the user when they wanted to type into the other ones;
  the tab stays as a read surface

LoadPreviousSession and FilterIncludePreviousSessions stay false to
keep the privacy-strict 'every session starts fresh' line. The
maintainer's personal settings flip them on, but that's an
opt-in choice, not a default we should ship to every fresh install.
RetentionEnabled also stays false for the same opt-in reason.

ChatTwo/Configuration.cs

@@ -152,15 +152,8 @@ public class Configuration : IPluginConfiguration
     public bool ShowTitleBar = true;
     public bool ShowPopOutTitleBar = true;
     public bool DatabaseBattleMessages;
-    // Load previously stored messages back into the tabs on plugin start
+    public bool LoadPreviousSession;
-    // so a /tell or party conversation picks up where it left off after
+    public bool FilterIncludePreviousSessions;
-    // a crash, restart or character switch. Default ON because the
-    // privacy filter already gates which channels go into the store at
-    // all; loading what is in there is not an additional privacy cost.
-    // Users can flip this off in Datenbank → Speicherung if they prefer
-    // every session to start with empty tabs.
-    public bool LoadPreviousSession = true;
-    public bool FilterIncludePreviousSessions = true;
     public bool SortAutoTranslate;
     public bool CollapseDuplicateMessages;
     public bool CollapseKeepUniqueLinks;

ChatTwo/Util/TabsUtil.cs

@@ -108,7 +108,10 @@ public static class TabsUtil
             [ChatType.LootNotice] = (ChatSourceExt.All, ChatSourceExt.All),
             [ChatType.LootRoll] = (ChatSourceExt.All, ChatSourceExt.All),
         },
-        Channel = InputChannel.Party,
+        // No automatic input-channel switch; the Gruppe tab is a read
+        // surface that pulls in Party, CrossParty, Alliance and PvpTeam
+        // together. Auto-routing /party into this tab would surprise the
+        // user when they actually wanted /alliance or /pvpteam.
     };
 
     public static Tab HellionBeginner => new()