Feat: Add Pipe Node

Introduces a new `Pipe` node to the Abstract Syntax Tree (AST).
This node represents a functional composition pattern, allowing
for chaining of operations.

The changes include:
- Defining the `Pipe` variant in `BoundKind` and `UntypedKind`.
- Implementing parsing logic for the `pipe` keyword.
- Adding handling for the `Pipe` node in various compiler passes
  (analyzer, binder, captures, dumper, macros, optimizer, TCO,
  type checker).
- Including a placeholder implementation for `Pipe` execution in the
  VM.
- Updating integration tests to use the new `pipe` syntax.

src/ast/nodes.rs

@@ -91,6 +91,10 @@ pub enum UntypedKind {
     Again {
         args: Box<Node<UntypedKind>>,
     },
+    Pipe {
+        inputs: Vec<Node<UntypedKind>>,
+        lambda: Box<Node<UntypedKind>>,
+    },
     Block {
         exprs: Vec<Node<UntypedKind>>,
     },