Pack plugins, shaders and client mods

• MC GUI's pack merged into ItemsAdder, Oraxen, Nexo, BetterHud, CraftEngine or RP Engine now loads on every client version, and the console says at startup whether each merge is right or what is missing. config.yml says how to merge into each one; merge again after every MC GUI update.
• MC GUI now loads before those pack plugins, so the folder they merge from is already there, and up to date, when they build their pack.
• Fixed: after a Dialog Engine drawn dialog, pages stopped drawing because Dialog Engine's pack sat on top of MC GUI's. MC GUI's pack goes back on top before a page opens.
• Players with shaders on (Iris or OptiFine) now see a short message saying how to turn them off, instead of a page that cannot draw and a pointer floating in the world. Change or blank it with views.shaders-notice.
• Fixed: Xaero's Minimap and JourneyMap covered pages and overlays. They are hidden while one is open.
• Fixed: with Lunar Client's Turbo Entity Mode (on by default), the pointer drifted. It stays put now.
• Fixed: a page opened in a one-block shaft, a low tunnel, lava or while buried showed the block, fire or water overlay over it.
• Bedrock players joining through Geyser are told screens are Java only, instead of being seated in a view they cannot see.
• Fixed: on Folia, a player teleported away while seated was put back on the seat.