refactor(client): 裸色字面量 F0F6FF/F0F4FF 迁移到 token

入库选填区/退单提示条 F0F6FF → infoSoft；表格列头 F0F4FF → thBg；
登录历史项/外壳用户菜单 hover → rowHover、菜单文字 → text。
深色主题 B / 暖色主题 C 下这些 chrome 现可正确随主题换色。

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01TSKEiHsvauyxYUW2itzUXX

client/lib/screens/stock_in/stock_in_form_screen.dart

@@ -984,7 +984,7 @@ class _StockInFormScreenState extends ConsumerState<StockInFormScreen> {
                   color: context.tokens.primaryDark)),
         );
     return Container(
-      color: const Color(0xFFF0F4FF),
+      color: context.tokens.thBg,
       child: Row(children: [
         SizedBox(width: 36, child: th('序号')),
         Expanded(flex: 18, child: th('名称')),
@@ -1115,7 +1115,7 @@ class _StockInFormScreenState extends ConsumerState<StockInFormScreen> {
   Widget _buildOptionalSection(_ItemRow item) {
     return Container(
       decoration: BoxDecoration(
-        color: const Color(0xFFF0F6FF),
+        color: context.tokens.infoSoft,
         border: Border(left: BorderSide(color: context.tokens.primary, width: 3)),
       ),
       padding: const EdgeInsets.fromLTRB(16, 10, 16, 14),

client/lib/screens/stock_in/stock_in_list_screen.dart

@@ -1201,7 +1201,7 @@ class _StockInDetailDialogState extends ConsumerState<_StockInDetailDialog> {
               },
               children: [
                 TableRow(
-                  decoration: const BoxDecoration(color: Color(0xFFF0F4FF)),
+                  decoration: BoxDecoration(color: context.tokens.thBg),
                   children: ['序号', '商品编码', '名称', '系列', '规格', '生产日期', '批次号', '数量', '单价', '金额']
                       .map((h) => Padding(
                             padding: const EdgeInsets.symmetric(