Add player health, lives, death, and cutscene system

Added player damage, invulnerability frames, knockback, and death handling. Enemies stop attacking after player death and player controls are disabled. Added a persistent three-life system with ambulance cutscenes after the first two deaths and a final Game Over cutscene after the third death.

Scripts/rscs/playerStats.tres

@@ -4,9 +4,9 @@
 
 [resource]
 script = ExtResource("1_eiyfu")
-max_health = 100
-starting_health = 100
-health = 100
+max_health = 3
+starting_health = 3
+health = 3
 meleeDamage = 5
 rangeDamage = 10
 metadata/_custom_type_script = "uid://b4t8cviiuvt18"