feat: Add type checking to the compiler

Introduces the `TypeChecker` struct and its associated `TypeContext` for
performing static type analysis on the abstract syntax tree.

This change includes:
- A new `type_checker.rs` module.
- Integration of `TypeChecker` into the `Environment::compile` method.
- Updates to `Environment` to manage global types.
- Renaming `bound_nodes.rs`'s `BoundNode` to `TypedNode` to reflect its
  type-checked nature.
- Refinements in binder and macro expansion to accommodate type
  information.

src/ast/compiler/binder.rs

@@ -11,7 +11,7 @@ struct LocalInfo {
     // Note: Binder doesn't strictly need the type anymore, 
     // but it might be useful for built-ins during resolution.
     // For now we keep it as Any or Unknown.
-    ty: StaticType, 
+    _ty: StaticType, 
 }
 
 #[derive(Debug, Clone)]
@@ -33,7 +33,7 @@ impl CompilerScope {
             return Err(format!("Variable '{}' is already defined in this scope level.", sym.name));
         }
         let slot = self.slot_count;
-        self.locals.insert(sym.clone(), LocalInfo { slot, ty: StaticType::Any });
+        self.locals.insert(sym.clone(), LocalInfo { slot, _ty: StaticType::Any });
         self.slot_count += 1;
         Ok(slot)
     }