Add scripted lightning weapon mods with interpolated anchored effects

mods/lightning_shield/scripts/equipment.rhai

@@ -0,0 +1,6 @@
+// Pickups use the same reusable equipment as the shop.
+fn on_pickup(event, state, random) {
+    let recovered = if state.contains("recovered") { state.recovered % 100000 + 1 } else { 1 };
+    #{ commands: [#{ op: "objective", key: "lightning_shield:recovered", value: recovered }],
+       state: #{ recovered: recovered } }
+}