feat: async/await 语法支持（AWAIT 帧快照挂起/恢复 + 微任务驱动 + AsyncFunction intrinsics）

crates/oxide_vm/src/session_gc.rs

@@ -95,6 +95,9 @@ impl SessionGc {
         if obj.is_promise_obj() {
             edges.extend(crate::promise::promise_native_edges(obj));
         }
+        if obj.is_async_obj() {
+            edges.extend(crate::async_func::async_native_edges(obj));
+        }
         // 遍历 upvalue cell 中的对象引用。
         for cell_ptr in obj.upvalues_slice() {
             if cell_ptr.is_null() {
@@ -164,6 +167,13 @@ impl SessionGc {
                 }
             }
         }
+        if obj.is_async_obj() {
+            for value in crate::async_func::async_native_edges(obj) {
+                if value.is_string() {
+                    live.insert(value.as_string_ptr_mut());
+                }
+            }
+        }
     }
 
     pub(crate) fn mark(&mut self, vm: &Vm) {
@@ -275,6 +285,7 @@ impl SessionGc {
             freed_bytes += data_view::drop_data_view_native(obj);
             freed_bytes += crate::generator::drop_generator_native(obj);
             freed_bytes += crate::promise::drop_promise_native(obj);
+            freed_bytes += crate::async_func::drop_async_native(obj);
 
             freed_bytes
         }
@@ -333,6 +344,8 @@ impl SessionGc {
                     data_view::clone_data_view_native_with_rewrite(old_ref, new_ref, |value| value);
                 } else if old_ref.is_promise_obj() {
                     crate::promise::clone_promise_native_with_rewrite(old_ref, new_ref, |value| value);
+                } else if old_ref.is_async_obj() {
+                    crate::async_func::clone_async_native_with_rewrite(old_ref, new_ref, |value| value);
                 }
                 forwarding.insert(old_ptr, new_ptr);
                 freed_bytes += Self::drop_session_object_heap_data(old_ptr);
@@ -366,6 +379,8 @@ impl SessionGc {
                 crate::generator::rewrite_generator_native(obj, |value| rewrite_forwarded_value(value, &forwarding));
             } else if obj.is_promise_obj() {
                 crate::promise::rewrite_promise_native(obj, |value| rewrite_forwarded_value(value, &forwarding));
+            } else if obj.is_async_obj() {
+                crate::async_func::rewrite_async_native(obj, |value| rewrite_forwarded_value(value, &forwarding));
             }
         }