style(sdk): SDK默认列表MD3容器化 — meow_listview_create默认container=1(行=surfaceContainer圆角卡+空隙+去分隔线+卡内tonal选中)，hello/files/ncm/reader等用默认renderer的App开箱即MD3(用户2026-09-04反馈默认仍扁平)；需平坦宿主可set_container(0)回退(宿主测试test_meow_ui_widgets/listvirt补set_container(0)锁扁平基线)。0warning，宿主测试全过(widgets ALL PASS/md3 PASS/swipe 35-0/listvirt 44-0)。meow_ui.a变需重编+重链四App

patch_v2/sdk/meow_ui_widget.c

@@ -1191,6 +1191,9 @@ meow_widget *meow_listview_create(int x, int y, int w, int h, int count,
     t->sel = -1; t->item_h = 56; t->scroll = 0; t->swipe_idx = -1;
     t->sel_mode = (mode >= MEOW_LIST_SEL_NONE && mode <= MEOW_LIST_SEL_MULTI) ? mode : MEOW_LIST_SEL_NONE;
     t->lines = 2; t->show_icon = 1; t->show_right = 1;   /* 默认双行富 item + 图标 + 右尾件（src2 布局不变） */
+    t->container = 1;   /* M6.37 P1：SDK 默认列表走 MD3 容器模式——行=surfaceContainer 圆角卡 + 空隙 + 去分隔线 + 卡内 tonal 选中，
+                         * 让 hello 示例 / files 及一切用 SDK 默认 renderer 的 App 开箱即 MD3（用户 2026-09-04 反馈默认仍扁平）。
+                         * 需扁平的宿主可显式 meow_listview_set_container(lv,0) 回退（test_meow_ui_widgets 即用它锁扁平基线）。 */
     if (t->sel_mode == MEOW_LIST_SEL_MULTI && t->count > 0) {
         t->sel_bits_n = (t->count + 31) / 32;
         t->sel_bits = (uint32_t *)calloc((size_t)t->sel_bits_n, sizeof(uint32_t));

patch_v2/sdk/test_meow_ui_listvirt.c

@@ -206,6 +206,7 @@ int main(void)
         /* 双行（lines=2，默认）：行 0 title+subtitle + icon(FOLDER) + 尾件(ARROW) */
         int lvx = 20, lvy = 50, lvw = 440, lvh = 120;
         meow_widget *lv = meow_listview_create(lvx, lvy, lvw, lvh, 0, NULL, NULL, MEOW_LIST_SEL_NONE);
+        meow_listview_set_container(lv, 0);   /* 锁扁平基线：SDK 默认已变 MD3 容器，本测试专测扁平虚拟化渲染路径 */
         CHECK(meow_listview_set_item_h(lv, itemh) == itemh, "item_h");
         CHECK(meow_listview_set_vsource(lv, vcount, vbind, NULL) == 0, "vsource");
         CHECK(meow_listview_set_item_renderer(lv, 2, 1, 1) == 0, "renderer");
@@ -267,6 +268,7 @@ int main(void)
         int lvx = 20, lvy = 50, lvw = 440, lvh = 120;
         g_count_override = 3; g_section_at = 1;
         meow_widget *lv = meow_listview_create(lvx, lvy, lvw, lvh, 0, NULL, NULL, MEOW_LIST_SEL_NONE);
+        meow_listview_set_container(lv, 0);   /* 锁扁平基线：SDK 默认已变 MD3 容器，段头 band 断言按扁平 */
         meow_listview_set_item_h(lv, itemh);
         meow_listview_set_vsource(lv, vcount, vbind, NULL);
         meow_ui_clear(th->bg);

patch_v2/sdk/test_meow_ui_widgets.c

@@ -318,6 +318,7 @@ int main(void)
      * lv 位于 (20,240,320,112)item_h=56 → 行0 y240..296、行1 296..352。
      * 断言全部「画完读 back_buf 像素」（region_has/px_near），非目检。 */
     meow_widget *lv = W(meow_listview_create(20, 240, 320, 112, 4, lv_src, NULL, MEOW_LIST_SEL_SINGLE));
+    meow_listview_set_container(lv, 0);   /* 锁扁平基线：SDK 默认已变 MD3 容器，此测试专测 set_container(0) 扁平回退路径 */
     assert(meow_listview_set_item_h(lv, 56) == 56);
     const meow_theme *lth = meow_theme_get();
     int lvx = 20, lvy = 240, lvw = 320, lvh = 112, itemh = 56;