refactor(settings): polish database tab section structure

Drop the redundant inner Advanced TreeNode in the Maintenance section,
flatten the duplicated indent in the Overview section, and rename the
section headings so they reflect their content (Overview shows
metadata, Maintenance hosts the shift-gated tooling).

ChatTwo/Resources/HellionStrings.de.resx

@@ -528,9 +528,9 @@
     <value>Speicherung</value>
   </data>
   <data name="Settings_Database_Viewer_Heading" xml:space="preserve">
-    <value>DB-Viewer</value>
+    <value>Übersicht</value>
   </data>
   <data name="Settings_Database_Stats_Heading" xml:space="preserve">
-    <value>Statistiken</value>
+    <value>Wartung</value>
   </data>
 </root>

ChatTwo/Resources/HellionStrings.resx

@@ -528,9 +528,9 @@
     <value>Storage</value>
   </data>
   <data name="Settings_Database_Viewer_Heading" xml:space="preserve">
-    <value>DB Viewer</value>
+    <value>Overview</value>
   </data>
   <data name="Settings_Database_Stats_Heading" xml:space="preserve">
-    <value>Statistics</value>
+    <value>Maintenance</value>
   </data>
 </root>

ChatTwo/Ui/SettingsTabs/Database.cs

@@ -103,9 +103,6 @@ internal sealed class Database : ISettingsTab
         if (!tree.Success)
             return;
 
-        using (ImRaii.PushIndent(ImGui.GetStyle().IndentSpacing, false))
-        {
-            ImGui.TextUnformatted(Language.Options_Database_Metadata_Heading);
         using (ImRaii.PushIndent(ImGui.GetStyle().IndentSpacing, false))
         {
             // Refresh the database size and message count every 5 seconds to avoid
@@ -156,7 +153,6 @@ internal sealed class Database : ISettingsTab
             }
         }
     }
-    }
 
     private void DrawStatsSection()
     {
@@ -169,7 +165,6 @@ internal sealed class Database : ISettingsTab
 
         using (ImRaii.PushIndent(ImGui.GetStyle().IndentSpacing, false))
         {
-            using var treeNode = ImRaii.TreeNode(Language.Options_Database_Advanced);
             using var wrap = ImRaii.TextWrapPos(0.0f);
 
             ImGuiUtil.WarningText(Language.Options_Database_Advanced_Warning);