fix(selection): Chip 禁用改成修饰器，只清消息、不删图标与选中态（复审 P2-1）

- 旧 API Chip::disabled(label, variant) 强制 leading/trailing/selected = None/false：实测
  assist 78→54、filter·on 74→50（连填充和勾都没了），禁用列里 filter·on 与 filter 逐像素同形
- 新 API Chip::assist(label, msg).leading(k).disabled()：只清 on_press，视觉信息全保留
  （research/12b §13 的禁用态是「容器/描边 12%、文字与图标 38%」——只降不删）
- 矩阵里禁用格改用修饰器，图标与选中态一并保留

crates/app-iced/src/components/selection/matrix.rs

@@ -163,22 +163,21 @@ fn draw(ui: &Ui, spec: Row, state: Interaction) -> Element<'_, ()> {
                 ChipVariant::Filter => "Filter",
                 ChipVariant::Input => "Input",
             };
-            let chip = if disabled {
-                Chip::disabled(label, variant)
-            } else {
-                match variant {
-                    ChipVariant::Assist => Chip::assist(label, ()).leading(IconKind::Download),
-                    // Filter 的勾只在**选中**时给（选中态才需要「已筛选」的强提示）
-                    ChipVariant::Filter if selected => {
-                        Chip::filter(label, true, ()).leading(IconKind::Check)
-                    }
-                    ChipVariant::Filter => Chip::filter(label, false, ()).leading(IconKind::Filter),
-                    // Input chip：前置图标 + 后置关闭键（avatar 位用图标代替）
-                    ChipVariant::Input => Chip::input(label, ())
-                        .leading(IconKind::Folder)
-                        .trailing(IconKind::Close),
+            // 禁用**只清消息**（`Chip::disabled()` 是修饰器）：图标与选中态必须保留，
+            // 否则禁用列里 `filter·on` 与 `filter` 会逐像素同形（复审 P2-1）。
+            let chip = match variant {
+                ChipVariant::Assist => Chip::assist(label, ()).leading(IconKind::Download),
+                // Filter 的勾只在**选中**时给（选中态才需要「已筛选」的强提示）
+                ChipVariant::Filter if selected => {
+                    Chip::filter(label, true, ()).leading(IconKind::Check)
                 }
+                ChipVariant::Filter => Chip::filter(label, false, ()).leading(IconKind::Filter),
+                // Input chip：前置图标 + 后置关闭键（avatar 位用图标代替）
+                ChipVariant::Input => Chip::input(label, ())
+                    .leading(IconKind::Folder)
+                    .trailing(IconKind::Close),
             };
+            let chip = if disabled { chip.disabled() } else { chip };
             selection::chip(ui, chip.state(state))
         }
     }