Was informed by the RetroAchievements team that this isn't an option in most emulators, and as the next commits will be to enable default icons, there will always be something to display.
Spectator Mode is a new mode added by rc_client that allows for achievement and leaderboard functionality, but does not submit this data to the site, partially allowing for offline achievements. It effectively replaces the former settings for disabling achievements, leaderboards, and RP, which are now always active internally as long as the client is active.
This adds the actual switch to turn on Hardcore Mode to the settings tab of the Achievements dialog. It is accompanied by a large tooltip warning explaining what it does and when it can be enabled.
The switch is only enabled to be turned on when no game is running, so that games are started in hardcore mode and can only be loaded via the console's memory card, as in the original hardware. Hardcore may be turned off while a game is running, but cannot be turned back on until the game is disabled.
The toggle trigger for hardcore mode also automatically disables the settings that are not allowed during hardcore mode.
Finally, the original flag in AchievementSettingsWidget to set whether things are enabled in hardcore mode (primarily Leaderboards) is replaced with the actual Hardcore Mode setting.
AchievementSettingsWidget is a dialog widget in AchievementsWindow for handling RetroAchievements settings in the user interface. This class contains the physical layout, widget connections, load/save functions and button responses. AchievementsWindow now has a tabbed list that this is inserted into; other tabs will be in a later pull request.