refactor(stmt): 还原 translate_with 直接属性访问（TPC 联合转换修复后）

TPC 6a67203 修复了联合类型转换 (X | t.CPtr)(arg) 后属性访问被丢弃的编译损坏，
9f7333b 引入的中间变量 workaround（call_ce/nm_cfn/ovn）不再需要，
还原为直接 ((ast.Call | t.CPtr)(ce)).func 等写法。

App/lib/core/Gen/StmtGenMixin.vp

@@ -261,10 +261,7 @@ class StmtGenMixin:
             cls_name: str = None
             ce: ast.AST | t.CPtr = item.context_expr
             if ce.kind() == ast.ASTKind.Call:
-                # 注意：联合类型转换后必须经中间变量再取属性（直接
-                # ((ast.Call|CPtr)(ce)).func 会被 TPC 编译损坏丢弃属性访问）
-                call_ce: ast.Call | t.CPtr = (ast.Call | t.CPtr)(ce)
-                cfn: ast.AST | t.CPtr = call_ce.func
+                cfn: ast.AST | t.CPtr = ((ast.Call | t.CPtr)(ce)).func
                 if cfn is not None:
                     if cfn.kind() == ast.ASTKind.Attribute:
                         ca: ast.Attribute | t.CPtr = (ast.Attribute | t.CPtr)(cfn)
@@ -279,8 +276,7 @@ class StmtGenMixin:
                         if cls_name is None:
                             cls_name = ca.attr
                     elif cfn.kind() == ast.ASTKind.Name:
-                        nm_cfn: ast.Name | t.CPtr = (ast.Name | t.CPtr)(cfn)
-                        cls_name = nm_cfn.id
+                        cls_name = ((ast.Name | t.CPtr)(cfn)).id
             # context 对象存入 __with_ctx（方法调用解析 self 用）
             ctx_alloca: llvmlite.Value | t.CPtr = llvmlite.build_alloca(
                 builder, ctx_val.Ty)
@@ -299,9 +295,7 @@ class StmtGenMixin:
             if item.optional_vars is not None:
                 ov: ast.AST | t.CPtr = item.optional_vars
                 if ov.kind() == ast.ASTKind.Name:
-                    # 联合类型转换后经中间变量再取属性（同 L264 注释，防 TPC 编译损坏）
-                    ovn: ast.Name | t.CPtr = (ast.Name | t.CPtr)(ov)
-                    asname: str = ovn.id
+                    asname: str = ((ast.Name | t.CPtr)(ov)).id
                     if asname is not None:
                         bind_val: llvmlite.Value | t.CPtr = enter_val
                         if bind_val is None: