feat: Add AST versioning system with automatic migration support

cli/src/commands/sdk.rs

@@ -246,13 +246,9 @@ fn load_stack_spec(
     let ast_json = fs::read_to_string(&ast.path)
         .with_context(|| format!("Failed to read stack file: {}", ast.path.display()))?;
 
-    let stack_spec: hyperstack_interpreter::ast::SerializableStackSpec =
-        serde_json::from_str(&ast_json).with_context(|| {
-            format!(
-                "Failed to deserialize stack AST from {}",
-                ast.path.display()
-            )
-        })?;
+    // Use versioned loader for automatic version detection and migration
+    let stack_spec = hyperstack_interpreter::versioned::load_stack_spec(&ast_json)
+        .with_context(|| format!("Failed to load stack AST from {}", ast.path.display()))?;
 
     if stack_spec.entities.is_empty() {
         return Err(anyhow::anyhow!(