feat: Add --no-opt flag and a failing test case

Introduce a --no-opt flag to disable compiler optimizations and add a
new integration test case to reproduce a slot clash issue during
inlining.

src/bin/ast.rs

@@ -42,8 +42,8 @@ struct Cli {
 
 fn main() {
     let cli = Cli::parse();
-    let env = Environment::new();
-    // Use env.optimization setting if needed, though it's currently on by default
+    let mut env = Environment::new();
+    env.optimization = !cli.no_opt;
     
     // Load libraries
     for lib_path in &cli.lib {