feat(ui06): App line A0-A7 — nav pill removal, light segments, bare summary, token alignment to app-preview

- tokens：次文字 #69778E、soft/card-border/seg 色组、输入圆角 10（kRadiusField）
- theme：导航 indicatorColor 透明+显式选中蓝；卡片去阴影改 1px #EDF0F5 边框；输入边框同步
- 新组件 SegmentTabs（#EDF1F6 轨道/选中实蓝/light 浅蓝变体/null 无高亮）替换 M3 SegmentedButton
- 上传中心：摘要去白卡直排+主数字 32/40；completed 次级筛选无高亮语义保留
- 相册卡 scrim 30% 起 #0C1728E8；导航角标红底白字白边；登录主标题 27/700
- theme_test 三处旧规格断言随 UI06 值更新；397/397 全绿、analyze 0 issues
- 真机证据：MuMu + 测试服务器 API，登录/相册/详情/上传 4 页截图确认达标
- 登记偏差：语义色保持对比度合规深色版；视口矩阵随 G2；详见验收记录 §6

Co-Authored-By: Claude Code <noreply@anthropic.com>

apps/mobile/lib/app/theme.dart

@@ -31,7 +31,7 @@ abstract final class AppTheme {
   static const Color _surface = Color(0xFFFFFFFF);
   static const Color _onSurface = Color(0xFF172033);
   static const Color _background = Color(0xFFF6F8FB);
-  static const Color _textSecondary = Color(0xFF5E6878);
+  static const Color _textSecondary = Color(0xFF69778E); // UI06: app-preview --muted
   static const Color _divider = Color(0xFFE5EAF1);
   static const Color _waiting = Color(0xFF996300);
   static const Color _onWaiting = Color(0xFFFFFFFF);
@@ -141,14 +141,15 @@ abstract final class AppTheme {
         ),
       ),
 
-      // 卡片：白色表面（深色深表面）、圆角 16、轻阴影。
+      // 卡片：白色表面、圆角 16、细边框无阴影（app-preview .card 形态）。
       cardTheme: CardThemeData(
         color: colorScheme.surface,
         surfaceTintColor: Colors.transparent,
-        elevation: 1,
-        shadowColor: Colors.black.withValues(alpha: dark ? 0.4 : 0.08),
+        elevation: 0,
+        shadowColor: Colors.transparent,
         shape: RoundedRectangleBorder(
           borderRadius: BorderRadius.circular(kRadiusCard),
+          side: BorderSide(color: dark ? _dividerDark : kColorCardBorder),
         ),
       ),
 
@@ -179,15 +180,26 @@ abstract final class AppTheme {
         actionTextColor: colorScheme.inversePrimary,
       ),
 
-      // 底部导航：白色表面（深色深表面）+ 派生容器色指示器。
+      // 底部导航（app-preview .nav）：白底 + 顶部细线 + **无胶囊指示器**；
+      // 选中 primary 蓝图标/文字，未选次文字色。
       navigationBarTheme: NavigationBarThemeData(
         backgroundColor: colorScheme.surface,
         surfaceTintColor: Colors.transparent,
-        indicatorColor: colorScheme.secondaryContainer,
-        height: 80,
-        labelTextStyle: WidgetStatePropertyAll(
-          textTheme.labelMedium!.copyWith(
-            color: colorScheme.onSurface,
+        indicatorColor: Colors.transparent,
+        height: 68,
+        iconTheme: WidgetStateProperty.resolveWith(
+          (states) => IconThemeData(
+            size: 24,
+            color: states.contains(WidgetState.selected)
+                ? colorScheme.primary
+                : (dark ? _textSecondaryDark : kColorTextSecondary),
+          ),
+        ),
+        labelTextStyle: WidgetStateProperty.resolveWith(
+          (states) => textTheme.labelMedium!.copyWith(
+            color: states.contains(WidgetState.selected)
+                ? colorScheme.primary
+                : (dark ? _textSecondaryDark : kColorTextSecondary),
             fontWeight: FontWeight.w500,
           ),
         ),
@@ -207,7 +219,7 @@ abstract final class AppTheme {
     Color color, {
     double width = 1,
   }) => OutlineInputBorder(
-    borderRadius: BorderRadius.circular(kRadiusInput),
+    borderRadius: BorderRadius.circular(kRadiusField),
     borderSide: BorderSide(color: color, width: width),
   );