add Lua sandbox with timer system (milestones 1-5 complete)

sandbox-test/scripts/test_cpu_limit.lua

@@ -0,0 +1,12 @@
+-- This script runs an infinite loop
+-- It should be stopped by the instruction limit hook
+
+local count = 0
+
+while true do
+    count = count + 1
+    -- This loop should be interrupted by instruction hook
+end
+
+-- Should never reach here
+error("FAIL: CPU limit not enforced - loop completed")