fix(client): 修复登录页候选词点击后未填入输入框

点击候选词时 pointer-down 先触发 TextField 失焦，focus listener
立即移除 Overlay，导致 InkWell.onTap (pointer-up) 执行时 widget
已不存在。改为失焦后延迟 150ms 关闭下拉框，给 onTap 足够时间填值。

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

client/lib/screens/auth/login_screen.dart

@@ -45,7 +45,8 @@ class _LoginScreenState extends ConsumerState<LoginScreen> {
         _openDropdown(_hotelLayerLink, _hotelCodeHistory, _shopCodeCtrl,
             isHotel: true);
       } else if (!_hotelCodeFocus.hasFocus) {
-        _closeHotel();
+        // 延迟关闭：让候选词的 onTap（pointer-up）先执行，再关闭下拉框
+        Future.delayed(const Duration(milliseconds: 150), _closeHotel);
       }
     });
     _usernameFocus.addListener(() {
@@ -53,7 +54,7 @@ class _LoginScreenState extends ConsumerState<LoginScreen> {
         _openDropdown(_usernameLayerLink, _usernameHistory, _usernameCtrl,
             isHotel: false);
       } else if (!_usernameFocus.hasFocus) {
-        _closeUsername();
+        Future.delayed(const Duration(milliseconds: 150), _closeUsername);
       }
     });
   }
@@ -117,29 +118,10 @@ class _LoginScreenState extends ConsumerState<LoginScreen> {
                   physics: const NeverScrollableScrollPhysics(),
                   itemCount: items.length,
                   separatorBuilder: (_, __) => const Divider(height: 1),
-                  itemBuilder: (_, i) => GestureDetector(
-                    behavior: HitTestBehavior.opaque,
-                    onTapDown: (_) {
-                      ctrl.text = items[i];
-                      ctrl.selection = TextSelection.collapsed(
-                          offset: items[i].length);
-                      if (isHotel) { _closeHotel(); } else { _closeUsername(); }
-                    },
-                    child: Padding(
-                      padding: const EdgeInsets.symmetric(
-                          horizontal: 12, vertical: 10),
-                      child: Row(
-                        children: [
-                          const Icon(Icons.history,
-                              size: 14, color: AppTheme.textSecondary),
-                          const SizedBox(width: 8),
-                          Text(items[i],
-                              style: const TextStyle(
-                                  fontSize: 14,
-                                  color: AppTheme.textPrimary)),
-                        ],
-                      ),
-                    ),
+                  itemBuilder: (_, i) => _HistoryMenuItem(
+                    value: items[i],
+                    onSelected: () =>
+                        _selectHistoryItem(items[i], ctrl, isHotel: isHotel),
                   ),
                 ),
               ),
@@ -158,6 +140,27 @@ class _LoginScreenState extends ConsumerState<LoginScreen> {
     setState(() {}); // refresh arrow icon
   }
 
+  void _selectHistoryItem(
+    String value,
+    TextEditingController ctrl, {
+    required bool isHotel,
+  }) {
+    ctrl.value = TextEditingValue(
+      text: value,
+      selection: TextSelection.collapsed(offset: value.length),
+    );
+
+    if (isHotel) {
+      _closeHotel();
+      _hotelCodeFocus.unfocus();
+    } else {
+      _closeUsername();
+      _usernameFocus.unfocus();
+    }
+
+    setState(() {});
+  }
+
   void _closeHotel() {
     _hotelEntry?.remove();
     _hotelEntry = null;
@@ -472,3 +475,52 @@ class _BackgroundPainter extends CustomPainter {
   @override
   bool shouldRepaint(covariant CustomPainter oldDelegate) => false;
 }
+
+class _HistoryMenuItem extends StatefulWidget {
+  final String value;
+  final VoidCallback onSelected;
+
+  const _HistoryMenuItem({
+    required this.value,
+    required this.onSelected,
+  });
+
+  @override
+  State<_HistoryMenuItem> createState() => _HistoryMenuItemState();
+}
+
+class _HistoryMenuItemState extends State<_HistoryMenuItem> {
+  bool _hovered = false;
+
+  @override
+  Widget build(BuildContext context) {
+    return MouseRegion(
+      onEnter: (_) => setState(() => _hovered = true),
+      onExit: (_) => setState(() => _hovered = false),
+      cursor: SystemMouseCursors.click,
+      child: Material(
+        color: _hovered ? const Color(0xFFF0F4FF) : Colors.white,
+        child: InkWell(
+          onTap: widget.onSelected,
+          child: Padding(
+            padding: const EdgeInsets.symmetric(horizontal: 12, vertical: 10),
+            child: Row(
+              children: [
+                const Icon(Icons.history,
+                    size: 14, color: AppTheme.textSecondary),
+                const SizedBox(width: 8),
+                Text(
+                  widget.value,
+                  style: const TextStyle(
+                    fontSize: 14,
+                    color: AppTheme.textPrimary,
+                  ),
+                ),
+              ],
+            ),
+          ),
+        ),
+      ),
+    );
+  }
+}