feat: 生成器基础支持（YIELD 帧快照挂起/恢复 + GeneratorPrototype next/return/throw）

- 新增 YIELD/SUSPEND_BODY opcode；function* 识别与 yield emit
- GeneratorState 全量快照 VM 执行上下文（regs/pc/bytecode/spill/save/try/cell 栈段/迭代器）
- 调用时参数初始化（默认值/解构副作用与异常在 g() 时刻生效）
- %GeneratorPrototype%/%GeneratorFunction.prototype% 内建对象与 next/return/throw
- session GC trace 生成器状态 JsValues；闭包捕获分析补 yield/赋值目标扫描

crates/oxide_vm/src/session_gc.rs

@@ -89,6 +89,9 @@ impl SessionGc {
         if obj.is_data_view_obj() {
             edges.extend(data_view::data_view_native_edges(obj));
         }
+        if obj.is_generator_obj() {
+            edges.extend(crate::generator::generator_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() {
@@ -144,6 +147,13 @@ impl SessionGc {
                 }
             }
         }
+        if obj.is_generator_obj() {
+            for value in crate::generator::generator_native_edges(obj) {
+                if value.is_string() {
+                    live.insert(value.as_string_ptr_mut());
+                }
+            }
+        }
     }
 
     pub(crate) fn mark(&mut self, vm: &Vm) {
@@ -253,6 +263,7 @@ impl SessionGc {
             freed_bytes += regexp::drop_regexp_native(obj);
             freed_bytes += typed_array::drop_typed_array_native(obj);
             freed_bytes += data_view::drop_data_view_native(obj);
+            freed_bytes += crate::generator::drop_generator_native(obj);
 
             freed_bytes
         }
@@ -338,6 +349,8 @@ impl SessionGc {
                 typed_array::rewrite_typed_array_native(obj, |value| rewrite_forwarded_value(value, &forwarding));
             } else if obj.is_data_view_obj() {
                 data_view::rewrite_data_view_native(obj, |value| rewrite_forwarded_value(value, &forwarding));
+            } else if obj.is_generator_obj() {
+                crate::generator::rewrite_generator_native(obj, |value| rewrite_forwarded_value(value, &forwarding));
             }
         }