20: Store variables keys without brackets

src/main/tjava/com/r35157/jupiterperpsalarm/impl/ref/AlarmConfigurationParser.tjava

@@ -237,9 +237,21 @@ public final class AlarmConfigurationParser {
 
         validateConstantName(name);
 
-        if (constants.putIfAbsent(name, value) != null) {
+        constants.put(parseVariableName(name), value);
-            throw new IllegalArgumentException("Duplicate constant: " + name);
     }
+
+    private static String parseVariableName(String variableName) {
+        if (!variableName.startsWith("{{") || !variableName.endsWith("}}")) {
+            throw new IllegalArgumentException("Invalid variable name: " + variableName);
+        }
+
+        String parsedVariableName = variableName.substring(2, variableName.length() - 2);
+
+        if (parsedVariableName.isBlank()) {
+            throw new IllegalArgumentException("Variable name cannot be blank: " + variableName);
+        }
+
+        return parsedVariableName;
     }
 
     private static String replaceConstants(