Bump app version to 1.0.538 and implement drone deployment feature

- Updated APP_VERSION in version.js and package.json to 1.0.538.
- Enhanced sandfront.html with new drone-related functionalities including:
  - Drone unit type with specific attributes.
  - New drone tech research and deployment mechanics.
  - Added drone orbiting behavior and cooldown management.
  - Implemented UI updates for drone deployment actions.
  - Adjusted game mechanics to support drone interactions and visibility.

Author: TimelessP

assets/js/version.js

@@ -1,6 +1,6 @@
 {
   "name": "idlegames",
-  "version": "1.0.536",
+  "version": "1.0.538",
   "description": "IdleGames PWA build tooling and deployment scripts.",
   "author": "Timeless Prototype",
   "license": "MIT",