feat(scala): m01–m06 port with shared fixtures

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

scala/solutions/Util.scala

@@ -0,0 +1,10 @@
+package snake
+
+/** m01 util: small helpers used by every later module. */
+object Util:
+
+  def range(n: Int): List[Int] = List.range(0, n)
+
+  def dropLast[A](xs: List[A]): List[A] = xs.dropRight(1)
+
+  def contains[A](xs: List[A], p: A, eq: (A, A) => Boolean): Boolean = xs.exists(x => eq(x, p))