1c2d361b77
When the user has both Hellion Chat and upstream Chat 2 installed and loaded, the parallel chat-window replacement and Hook collisions can crash FFXIV at frame boundaries. The new detector inspects IDalamudPluginInterface.InstalledPlugins and throws an InvalidOperationException with a localized message if Chat 2 is loaded, which Dalamud surfaces cleanly instead of letting the load proceed into a runtime crash. Bilingual messages (EN/DE) follow the existing HellionStrings pattern.