test(app-iced): M75 —— probe 分隔线判据改为「非底色长横线」+ 修 forced 改成 Option 后的两处测试

线在 fractional y 上被抗锯齿摊到两行，按精确 OutlineVariant 色匹配抓不到（实测 0 行）；
改为「非 Surface 的长横线」计数，断言 2..=6 行（两条线 × 各 1~2 行）。

crates/app-iced/src/components/buttons/tests.rs

@@ -212,7 +212,7 @@ fn icon_button_variants_match_the_reference_roles() {
     }
 }
 
-fn spec_of(variant: Variant, forced: Interaction) -> StyleSpec {
+fn spec_of(variant: Variant, forced: Option<Interaction>) -> StyleSpec {
     let (fill, content, border) = variant.roles();
     StyleSpec {
         fill,
@@ -220,7 +220,7 @@ fn spec_of(variant: Variant, forced: Interaction) -> StyleSpec {
         border,
         shape: variant.shape(),
         radius_side: Geometry::of(&light(), variant, false).height,
-        forced: Some(forced),
+        forced,
     }
 }
 
@@ -228,7 +228,7 @@ fn spec_of(variant: Variant, forced: Interaction) -> StyleSpec {
 #[test]
 fn outlined_style_draws_hairline_border_and_full_radius() {
     let ui = light();
-    let style = style_closure(&ui, spec_of(Variant::Outlined, Interaction::Enabled));
+    let style = style_closure(&ui, spec_of(Variant::Outlined, None));
 
     let idle = style(&ui.theme(), button::Status::Active);
     assert_eq!(idle.background, None, "Outlined 静息容器必须透明");
@@ -255,7 +255,7 @@ fn outlined_style_draws_hairline_border_and_full_radius() {
 #[test]
 fn filled_button_state_layers_are_visible_and_ordered() {
     let ui = light();
-    let style = style_closure(&ui, spec_of(Variant::Filled, Interaction::Enabled));
+    let style = style_closure(&ui, spec_of(Variant::Filled, None));
 
     let idle = style(&ui.theme(), button::Status::Active);
     let hovered = style(&ui.theme(), button::Status::Hovered);
@@ -283,7 +283,7 @@ fn filled_button_state_layers_are_visible_and_ordered() {
 #[test]
 fn forced_state_overrides_the_runtime_status() {
     let ui = light();
-    let style = style_closure(&ui, spec_of(Variant::Tonal, Interaction::Hovered));
+    let style = style_closure(&ui, spec_of(Variant::Tonal, Some(Interaction::Hovered)));
     // 运行期说 Active，但取证要 hover → 必须画 hover
     assert_eq!(
         style(&ui.theme(), button::Status::Active).background,
@@ -300,7 +300,7 @@ fn forced_state_overrides_the_runtime_status() {
 #[test]
 fn elevated_uses_a_tone_not_a_shadow() {
     let ui = light();
-    let style = style_closure(&ui, spec_of(Variant::Elevated, Interaction::Enabled));
+    let style = style_closure(&ui, spec_of(Variant::Elevated, None));
     let idle = style(&ui.theme(), button::Status::Active);
     assert_eq!(idle.shadow, Shadow::default(), "rubric §7：L1 不画阴影");
     assert_eq!(