Setup framework for running days from single command

bin/adventofcode2025.dart

@@ -1,5 +1,29 @@
-import 'package:adventofcode2025/adventofcode2025.dart' as adventofcode2025;
+import 'dart:io';
+
+import 'package:adventofcode2025/day1/main.dart' as day1;
+
+import 'package:args/args.dart';
+
+const help = 'help';
+const dayNumber = 'day';
 
 void main(List<String> arguments) {
-  print('Hello world: ${adventofcode2025.calculate()}!');
+  final parser = ArgParser()
+    ..addFlag(help, negatable: false, abbr: 'h')
+    ..addOption(dayNumber, mandatory: true, abbr: "d");
+  var results = parser.parse(arguments);
+
+  if (results.flag(help)) {
+    print(parser.usage);
+    exit(0);
+  }
+
+  var day = results.option(dayNumber);
+
+  switch (day) {
+    case '1':
+      day1.run();
+    default:
+      print("'$day' is not a valid value for option $dayNumber");
+  }
 }