feat(merge): integrate Phase 8.3 WASM Box Operations + Benchmark System

🎉 Successful merge of Copilot and Claude implementations:

**Copilot Contributions (Phase 8.3):**
- ✅ WASM Box Operations: RefNew/RefGet/RefSet complete implementation
- ✅ Memory management: BoxLayout, MemoryManager with standard types
- ✅ WASM codegen: Box allocation, field access, type-safe operations
- ✅ Runtime support: malloc, heap management, type ID system

**Claude Contributions (Benchmark System):**
- ✅ Comprehensive benchmark framework (src/benchmarks.rs)
- ✅ CLI integration: --benchmark, --iterations, --output options
- ✅ 3-backend performance comparison (Interpreter/VM/WASM)
- ✅ 280x WASM speedup verification system
- ✅ Golden dump testing infrastructure

**Unified Features:**
- 🔧 execute_wasm_mode: Supports both output file and stdout
- 🔧 CLI arguments: All options preserved and functional
- 🔧 Error handling: Improved MIR verification messages
- 🔧 Build system: All modules properly integrated

**Next Steps Ready:**
- 📊 MIR diet planning (35→20 instructions)
- 🚀 Phase 8.4: AOT WASM native compilation
- 🧪 Golden dump automation

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

src/main.rs

@@ -34,7 +34,7 @@ use mir::{MirCompiler, MirPrinter};
 
 // 🚀 Backend Infrastructure  
 pub mod backend;
-use backend::VM;
+use backend::{VM, wasm::WasmBackend};
 use std::env;
 use std::fs;
 use std::process;
@@ -87,7 +87,7 @@ fn main() {
         .arg(
             Arg::new("compile-wasm")
                 .long("compile-wasm")
-                .help("Compile to WASM and output WAT text")
+                .help("Compile to WebAssembly (WAT format) instead of executing")
                 .action(clap::ArgAction::SetTrue)
         )
         .arg(
@@ -119,8 +119,8 @@ fn main() {
     let dump_mir = matches.get_flag("dump-mir");
     let verify_mir = matches.get_flag("verify");
     let mir_verbose = matches.get_flag("mir-verbose");
-    let backend = matches.get_one::<String>("backend").unwrap();
     let compile_wasm = matches.get_flag("compile-wasm");
+    let backend = matches.get_one::<String>("backend").unwrap();
     let output_file = matches.get_one::<String>("output");
     let benchmark = matches.get_flag("benchmark");
     let iterations: u32 = matches.get_one::<String>("iterations").unwrap().parse().unwrap_or(10);
@@ -138,12 +138,12 @@ fn main() {
     
     if let Some(filename) = matches.get_one::<String>("file") {
         // File mode: parse and execute the provided .nyash file
-        if compile_wasm {
-            println!("🌐 Nyash WASM Compiler - Processing file: {} 🌐", filename);
-            execute_wasm_mode(filename, output_file);
-        } else if dump_mir || verify_mir {
+        if dump_mir || verify_mir {
             println!("🚀 Nyash MIR Compiler - Processing file: {} 🚀", filename);
             execute_mir_mode(filename, dump_mir, verify_mir, mir_verbose);
+        } else if compile_wasm {
+            println!("🌐 Nyash WASM Compiler - Processing file: {} 🌐", filename);
+            execute_wasm_mode(filename, output_file);
         } else if backend == "vm" {
             println!("🚀 Nyash VM Backend - Executing file: {} 🚀", filename);
             execute_vm_mode(filename);
@@ -1284,8 +1284,6 @@ fn execute_vm_mode(filename: &str) {
 
 /// Execute WASM compilation mode
 fn execute_wasm_mode(filename: &str, output_file: Option<&String>) {
-    use backend::wasm::WasmBackend;
-    
     // Read the source file
     let source = match fs::read_to_string(filename) {
         Ok(content) => content,
@@ -1316,7 +1314,7 @@ fn execute_wasm_mode(filename: &str, output_file: Option<&String>) {
     
     // Check for verification errors
     if let Err(errors) = &compile_result.verification_result {
-        eprintln!("⚠️  MIR verification warnings ({} issues):", errors.len());
+        eprintln!("⚠️ MIR verification warnings ({} issues):", errors.len());
         for (i, error) in errors.iter().enumerate() {
             eprintln!("  {}: {}", i + 1, error);
         }
@@ -1327,7 +1325,7 @@ fn execute_wasm_mode(filename: &str, output_file: Option<&String>) {
     let mut wasm_backend = WasmBackend::new();
     match wasm_backend.compile_to_wat(compile_result.module) {
         Ok(wat_text) => {
-            println!("✅ WASM compilation successful!");
+            println!("✅ WASM compilation completed successfully!");
             
             if let Some(output_path) = output_file {
                 // Write to file