Refactor: Replace optimization level with boolean flag

The optimizer now uses a simple boolean flag (`optimization`) instead of
an `optimization_level` (u32). This simplifies the optimizer's logic and
makes it easier to enable or disable optimizations.

The command-line interface and internal testing have been updated to
reflect this change.

src/ast/environment.rs

@@ -26,7 +26,7 @@ pub struct Environment {
     pub function_registry: Rc<RefCell<HashMap<u32, BoundNode>>>,
     pub monomorph_cache: Rc<RefCell<MonoCache>>,
     pub debug_mode: bool,
-    pub optimization_level: u32,
+    pub optimization: bool,
 }
 
 struct EnvFunctionRegistry {
@@ -91,7 +91,7 @@ impl Environment {
             function_registry: Rc::new(RefCell::new(HashMap::new())),
             monomorph_cache: Rc::new(RefCell::new(HashMap::new())),
             debug_mode: false,
-            optimization_level: 2,
+            optimization: true,
         };
         env.register_stdlib();
         env
@@ -189,7 +189,7 @@ impl Environment {
         let specialized = self.specialize_node(node);
 
         // 2. Optimize (Level 1: Cracking, Level 2: Collapsing)
-        let optimizer = Optimizer::new(self.optimization_level)
+        let optimizer = Optimizer::new(self.optimization)
             .with_globals(self.global_values.clone())
             .with_purity(self.global_purity.clone());
         let optimized = optimizer.optimize(specialized);
@@ -210,7 +210,7 @@ impl Environment {
         let global_values = self.global_values.clone();
         let global_types = self.global_types.clone();
         let global_purity = self.global_purity.clone();
-        let opt_level = self.optimization_level;
+        let optimization = self.optimization;
 
         let compiler = Rc::new(
             move |func_template: BoundNode,
@@ -237,7 +237,7 @@ impl Environment {
                 let specialized_ast = sub_specializer.specialize(retyped_ast);
 
                 // 3. Optimize (Phase 2: Cracking & Folding)
-                let optimizer = Optimizer::new(opt_level)
+                let optimizer = Optimizer::new(optimization)
                     .with_globals(global_values.clone())
                     .with_purity(global_purity.clone());
                 let optimized_ast = optimizer.optimize(specialized_ast);