added main game loop

main.py

@@ -0,0 +1,17 @@
+import pygame
+from constants import *
+
+def main():
+    print("Starting asteroids!")
+    print(f"Screen width: {SCREEN_WIDTH}")
+    print(f"Screen height: {SCREEN_HEIGHT}")
+    pygame.init()
+    screen = pygame.display.set_mode((SCREEN_WIDTH, SCREEN_HEIGHT))
+    while True:
+        for event in pygame.event.get():
+            if event.type == pygame.QUIT:
+                return
+        screen.fill((0, 0, 0))  # simplified fill call
+        pygame.display.flip()    # fixed typo in flip
+if __name__ == "__main__":
+    main()