Add desktop shortcuts, document the real Prism export zip format

install.ps1/install.sh now create a desktop shortcut/.desktop entry
that launches straight into the game, so participants don't have to
re-run the install script or hunt through folders after closing the
launcher once.

Also root-caused the "no instance in Fjord" report: Prism's Export
Instance zips the instance contents (instance.cfg, mmc-pack.json,
minecraft/) directly at the zip root, NOT wrapped in a folder named
after the instance like HOSTING.md assumed. Fixed by repackaging the
live modpack.zip server-side with the correct LANParty/ wrapper
(verified real exported files - actual Java path, real playtime
stats, not fabricated). HOSTING.md still needs a correction pass to
stop telling people to expect a pre-wrapped export.

install.sh

@@ -97,5 +97,20 @@ else
   echo "==> Instance already present, skipping download"
 fi
 
+# Desktop shortcut so the game is findable after closing it, without re-running this script
+DESKTOP_DIR="$(xdg-user-dir DESKTOP 2>/dev/null || echo "$HOME/Desktop")"
+if [[ -d "$DESKTOP_DIR" ]]; then
+  cat > "$DESKTOP_DIR/lan-party-minecraft.desktop" <<EOF
+[Desktop Entry]
+Type=Application
+Name=LAN Party Minecraft
+Exec=$LAUNCHER_BIN --dir "$INSTALL_DIR" --launch "$INSTANCE_NAME" --profile "$NICK" --server "$SERVER_ADDR"
+Icon=$INSTALL_DIR/app/resources/multimc.png
+Terminal=false
+EOF
+  chmod +x "$DESKTOP_DIR/lan-party-minecraft.desktop"
+  echo "==> Desktop shortcut created: $DESKTOP_DIR/lan-party-minecraft.desktop (double-click this next time instead of re-running the install script — may need 'Allow Launching' on first click, GNOME/KDE trust new .desktop files by default)"
+fi
+
 echo "==> Launching into $INSTANCE_NAME as $NICK, joining $SERVER_ADDR"
 "$LAUNCHER_BIN" --dir "$INSTALL_DIR" --launch "$INSTANCE_NAME" --profile "$NICK" --server "$SERVER_ADDR"