Patch v0.99.21

Fixed a bug where newly created maps sometimes had incorrect map sizes.
Fixed a bug where movable buildings could not be placed at map boundaries.
Fixed incorrect textures for the Stone Cannon.
Added validation for spawn points in the map editor to reduce incorrect spawn point placement.
Fixed a bug where the Crystal Tower would fire multiple missiles after upgrading.
Fixed incorrect charge bonuses for Orc Cavalry.
High-quality blueprints now have a small chance to add a card with 1 usage count.
Taverns no longer have a minimum food requirement for harvesting gold.
Updated the assets for Spearmen and Spear Guards, thanks to the help of a talented group member.
Fixed incorrect duration for the Strong Paralysis effect.
Enhanced the upgrade effects of Rolling Logs.
Optimized code to reduce lag.
Fixed a bug where custom maps could cause errors in endless mode due to monster spawning.
Fixed a bug where walls had incorrect health after upgrading.