Clarify the privacy filter only governs storage, not the live chat log

Audit finding M-5. The master switch description told users what the
filter does to the database, but nothing in the UI ruled out the
common misreading "if I disable a channel, it will also disappear
from the chat log". A help-text line under the toggle now states
explicitly that the filter is storage-only and points at the
in-game chat tab filters for hiding channels visually. EN and DE
strings added together.

ChatTwo/Ui/SettingsTabs/Privacy.cs

@@ -104,6 +104,8 @@ internal sealed class Privacy : ISettingsTab
             HellionStrings.Privacy_FilterEnabled_Name,
             HellionStrings.Privacy_FilterEnabled_Description);
 
+        ImGuiUtil.HelpText(HellionStrings.Privacy_FilterEnabled_StorageOnly_Help);
+
         ImGui.Spacing();
         ImGui.Separator();
         ImGui.Spacing();