extend unlock logic to support multi-node unlock plans and update version number

src/main/java/net/fretux/skillengine/client/ClientKeybinds.java

@@ -23,5 +23,9 @@ public class ClientKeybinds {
                 "key.categories.ui"
         );
         event.register(OPEN_ABILITIES);
+
+        event.register(AbilityKeybindHandler.ABILITY_1);
+        event.register(AbilityKeybindHandler.ABILITY_2);
+        event.register(AbilityKeybindHandler.ABILITY_3);
     }
 }

src/main/java/net/fretux/skillengine/client/SkilltreeClientState.java

@@ -18,11 +18,15 @@ public class SkilltreeClientState {
     private static final int[] clientCooldowns = new int[3];
 
     public static void updateCooldown(int slot, int cd) {
-        clientCooldowns[slot - 1] = cd;
+        int index = slot - 1;
+        if (index < 0 || index >= clientCooldowns.length) return;
+        clientCooldowns[index] = Math.max(0, cd);
     }
 
     public static int getClientCooldown(int slot) {
-        return clientCooldowns[slot - 1];
+        int index = slot - 1;
+        if (index < 0 || index >= clientCooldowns.length) return 0;
+        return clientCooldowns[index];
     }
 
     public static void unlockNode(ResourceLocation id) {