feat: Implement AST macros and templates

This commit introduces support for AST macros and templates, enabling
users to define and use custom, reusable components within the visual
DSL.

Key changes include:
- A new `MacroRegistry` to manage macro definitions.
- A `MacroExpander` to process macro calls and expand templates.
- A `MacroEvaluator` trait for evaluating expressions during expansion.
- The `Expansion` node in `BoundKind` to preserve the original macro
  call and its expanded form for debugging.
- Updates to the `Binder`, `Dumper`, and `UpvalueAnalyzer` to handle the
  new macro constructs.
- New examples demonstrating various macro functionalities like
  `unless`, splicing, and nested macros.

examples/data.myc

@@ -1,5 +1,5 @@
 ;; Complex Data Structure Test
-;; Benchmark: 64.4us
+;; Benchmark: 49.8us
 ;; Output: {:input 10, :name "Fibonacci", :output 55}
 (do
   (def fib (fn [n]