feature: map rotation and per-server plugins on the dedicated server page

[lukepolo]

Adds Map Rotation and Plugins cards to the dedicated server page (admins, non-Ranked/Practice servers on a node).

• Map Rotation: ordered list from the maps catalog, reorder/remove, shuffle, and Import Workshop Collection (link or ID)
• Shows which plugin plays the rotation, or links to install MapChooser when none is installed
• Plugins: Default / On / Off per installed game plugin for this server; mode plugins shown as locked
• Both save with Save & Restart; raw gql until codegen picks up the new schema