feat(stdlib): implement compose/flip/pipe in Core.as, fix Display for Int

Core.as: Added compose (function composition), flip (argument order
reversal), and pipe (function application) — lambda syntax works now.
traits.as: Display for Int now delegates to int_to_string builtin
instead of returning placeholder "int".

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: hyperpolymath

stdlib/Core.as

@@ -15,8 +15,20 @@ pub fn const[A, B](x: A, own y: B) -> A {
   return x;
 }
 
-// TODO: Function composition and flip require lambda syntax
-// which is not yet fully supported by the parser
+/// Function composition: (f >> g)(x) = g(f(x))
+pub fn compose[A, B, C](f: A -> B, g: B -> C) -> (A -> C) {
+  return fn(x: A) -> C { g(f(x)) };
+}
+
+/// Flip argument order: flip(f)(a, b) = f(b, a)
+pub fn flip[A, B, C](f: (A, B) -> C) -> ((B, A) -> C) {
+  return fn(b: B, a: A) -> C { f(a, b) };
+}
+
+/// Apply a function to a value (pipe operator)
+pub fn pipe[A, B](x: A, f: A -> B) -> B {
+  return f(x);
+}
 
 // Comparison operators
 

stdlib/traits.as

@@ -157,8 +157,7 @@ impl Hash for Int {
 
 impl Display for Int {
   pub fn to_string(ref self) -> String {
-    // TODO: Implement actual int-to-string conversion
-    return "int";
+    return int_to_string(*self);
   }
 }