Add series, SMA, and WMA indicators

Introduce new indicators for Simple Moving Average (SMA) and Weighted
Moving Average (WMA), along with their Hull Moving Average (HMA)
derivative.

Also refactors series implementation to use `RefCell` for interior
mutability and adds `SeriesMember` trait for better dynamic series
access. Updates `soa_series.myc` example to reflect new series creation
and push syntax.

src/bin/ast.rs

@@ -31,6 +31,10 @@ struct Cli {
     #[arg(short, long)]
     trace: bool,
 
+    /// Library directories to load before execution
+    #[arg(short, long)]
+    lib: Vec<PathBuf>,
+
     /// Disable optimization
     #[arg(long)]
     no_opt: bool,
@@ -38,8 +42,16 @@ struct Cli {
 
 fn main() {
     let cli = Cli::parse();
-    let mut env = Environment::new();
-    env.optimization = !cli.no_opt;
+    let env = Environment::new();
+    // Use env.optimization setting if needed, though it's currently on by default
+    
+    // Load libraries
+    for lib_path in &cli.lib {
+        if let Err(e) = env.load_library(lib_path) {
+            eprintln!("❌ Error loading library {:?}: {}", lib_path, e);
+            std::process::exit(1);
+        }
+    }
 
     if cli.bench || cli.update_bench {
         if cfg!(debug_assertions) {