🆙 Added null check to wall /floor and background

Database Updates/Set Rooms wallitems/fix_room_paint_null.sql

@@ -0,0 +1,15 @@
+-- Fix NULL room paint columns
+--
+-- Some legacy/imported rooms have NULL in paper_wall / paper_floor / paper_landscape.
+-- The server compares these with .equals("0.0") on room entry, which throws a
+-- NullPointerException (RoomManager.openRoom) and prevents the room from loading.
+-- This normalizes existing NULL values and re-enforces the NOT NULL DEFAULT '0.0'
+-- constraint so it cannot happen again.
+
+UPDATE `rooms` SET `paper_wall`      = '0.0' WHERE `paper_wall`      IS NULL;
+UPDATE `rooms` SET `paper_floor`     = '0.0' WHERE `paper_floor`     IS NULL;
+UPDATE `rooms` SET `paper_landscape` = '0.0' WHERE `paper_landscape` IS NULL;
+
+ALTER TABLE `rooms` MODIFY COLUMN `paper_wall`      VARCHAR(50) NOT NULL DEFAULT '0.0';
+ALTER TABLE `rooms` MODIFY COLUMN `paper_floor`     VARCHAR(50) NOT NULL DEFAULT '0.0';
+ALTER TABLE `rooms` MODIFY COLUMN `paper_landscape` VARCHAR(50) NOT NULL DEFAULT '0.0';