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/compiler/optimizer/engine.rs

@@ -386,6 +386,21 @@ impl Optimizer {
                 )
             }
 
+            BoundKind::Pipe { inputs, lambda } => {
+                let mut o_inputs = Vec::with_capacity(inputs.len());
+                for input in inputs {
+                    o_inputs.push(self.visit_node(input, sub, path));
+                }
+                let o_lambda = Box::new(self.visit_node(*lambda, sub, path));
+                (
+                    BoundKind::Pipe {
+                        inputs: o_inputs,
+                        lambda: o_lambda,
+                    },
+                    node.ty.clone(),
+                )
+            }
+
             BoundKind::Block { ref exprs } => {
                 let mut info = UsageInfo::default();
                 if !exprs.is_empty() {