feat: Phase 2 — upgrade deps to null-safe, replace deprecated packages

- pubspec: bump all maintained deps to null-safe latest; flutter pub get resolves
- Remove 12 packages (0-ref or no null-safe): splashscreen, flappy_search_bar,
  searchable_dropdown, share, platform_detect, flutter_inappwebview, countdown,
  gender_selection, flutter_dash, smooth_star_rating, hovering, ffi
- Add flutter_rating_bar
- Keep discontinued-but-null-safe for now (Phase 5): pull_to_refresh, hive, catcher
- New null-safe custom components (API-compatible, callers change only imports):
  utils/countdown.dart, widgets/general/{hover_widget,gender_selection,
  smooth_star_rating,search_bar}.dart
- main.dart: drop dead SplashScreen _buildBody + _to field
- 23 consuming files: swap deprecated imports to local components

Null-safety migration + upgraded-API adaptation = Phase 3.

lib/widgets/general/gender_selection.dart

@@ -0,0 +1,111 @@
+import 'package:flutter/material.dart';
+
+/// 自定义实现，替代已停维的 `gender_selection` 包。
+///
+/// 保留原 `Gender` 枚举与 `GenderSelection` 组件的命名参数，
+/// 使调用方仅改 import 即可编译。大部分装饰性参数为兼容保留（暂未全部生效，
+/// 后续美化阶段 Phase 5 再完善视觉）。
+enum Gender { Male, Female }
+
+class GenderSelection extends StatefulWidget {
+  final String? maleText;
+  final String? femaleText;
+  final Color? selectedGenderIconBackgroundColor;
+  final Alignment? checkIconAlignment;
+  final IconData? selectedGenderCheckIcon;
+  final void Function(Gender gender)? onChanged;
+  final bool? equallyAligned;
+  final Duration? animationDuration;
+  final bool? isCircular;
+  final bool? isSelectedGenderIconCircular;
+  final double? opacityOfGradient;
+  final EdgeInsets? padding;
+  final double? size;
+  final Gender? selectedGender;
+
+  const GenderSelection({
+    super.key,
+    this.maleText,
+    this.femaleText,
+    this.selectedGenderIconBackgroundColor,
+    this.checkIconAlignment,
+    this.selectedGenderCheckIcon,
+    this.onChanged,
+    this.equallyAligned,
+    this.animationDuration,
+    this.isCircular,
+    this.isSelectedGenderIconCircular,
+    this.opacityOfGradient,
+    this.padding,
+    this.size,
+    this.selectedGender,
+  });
+
+  @override
+  State<GenderSelection> createState() => _GenderSelectionState();
+}
+
+class _GenderSelectionState extends State<GenderSelection> {
+  Gender? _selected;
+
+  @override
+  void initState() {
+    super.initState();
+    _selected = widget.selectedGender;
+  }
+
+  Widget _buildOption(Gender gender, String label) {
+    final selected = _selected == gender;
+    final color = widget.selectedGenderIconBackgroundColor ?? Colors.indigo;
+    return Expanded(
+      child: Padding(
+        padding: widget.padding ?? const EdgeInsets.all(3.0),
+        child: InkWell(
+          onTap: () {
+            setState(() => _selected = gender);
+            widget.onChanged?.call(gender);
+          },
+          child: Container(
+            height: widget.size ?? 50.0,
+            alignment: Alignment.center,
+            decoration: BoxDecoration(
+              color: selected ? color : color.withOpacity(0.06),
+              borderRadius:
+                  (widget.isCircular ?? false) ? BorderRadius.circular(60) : null,
+              border: Border.all(
+                color: selected ? color : Colors.black26,
+                width: selected ? 2 : 1,
+              ),
+            ),
+            child: Row(
+              mainAxisSize: MainAxisSize.min,
+              children: [
+                if (selected && widget.selectedGenderCheckIcon != null)
+                  Icon(widget.selectedGenderCheckIcon, color: Colors.white, size: 18),
+                if (selected && widget.selectedGenderCheckIcon != null)
+                  const SizedBox(width: 6),
+                Text(
+                  label,
+                  style: TextStyle(
+                    color: selected ? Colors.white : Colors.black87,
+                    fontWeight: FontWeight.w600,
+                  ),
+                ),
+              ],
+            ),
+          ),
+        ),
+      ),
+    );
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    return Row(
+      children: <Widget>[
+        _buildOption(Gender.Male, widget.maleText ?? 'Mr'),
+        _buildOption(Gender.Female, widget.femaleText ?? 'Ms'),
+      ],
+    );
+  }
+}

lib/widgets/general/hover_widget.dart

@@ -0,0 +1,46 @@
+import 'package:flutter/material.dart';
+
+/// 自定义实现，替代已停维的 `hovering` 包的 [HoverWidget]。
+///
+/// API 兼容：
+/// ```dart
+/// HoverWidget(
+///   child: ...,
+///   hoverChild: ...,
+///   onHover: (PointerHoverEvent event) { ... },
+/// )
+/// ```
+///
+/// 鼠标悬停时显示 [hoverChild]，否则显示 [child]。
+class HoverWidget extends StatefulWidget {
+  final Widget child;
+  final Widget? hoverChild;
+  final void Function(PointerHoverEvent)? onHover;
+
+  const HoverWidget({
+    super.key,
+    required this.child,
+    this.hoverChild,
+    this.onHover,
+  });
+
+  @override
+  State<HoverWidget> createState() => _HoverWidgetState();
+}
+
+class _HoverWidgetState extends State<HoverWidget> {
+  bool _hovering = false;
+
+  @override
+  Widget build(BuildContext context) {
+    return MouseRegion(
+      cursor: SystemMouseCursors.click,
+      onHover: widget.onHover,
+      onEnter: (_) => setState(() => _hovering = true),
+      onExit: (_) => setState(() => _hovering = false),
+      child: (_hovering && widget.hoverChild != null)
+          ? widget.hoverChild!
+          : widget.child,
+    );
+  }
+}

lib/widgets/general/payment_verification_code_dialog.dart

@@ -1,5 +1,5 @@
 
-import 'package:countdown/countdown.dart';
+import '../utils/countdown.dart';
 import 'package:flutter/material.dart';
 import 'package:pinput/pin_put/pin_put.dart';
 

lib/widgets/general/search_bar.dart

@@ -0,0 +1,185 @@
+import 'dart:async';
+
+import 'package:flutter/material.dart';
+
+/// 轻量级异步搜索控制器，配合 [SearchBar] 使用。
+///
+/// 替代已停维的 `flappy_search_bar` 的 `SearchBarController`。
+/// 保留泛型 `<T>` 以兼容调用方 `SearchBarController<Product>()` 写法。
+/// [replayLastSearch] 用于“加载更多 / 分页”：外部 page++ 后触发重跑上一次搜索。
+class SearchBarController<T> {
+  String lastQuery = '';
+  VoidCallback? _replay;
+
+  void _register(VoidCallback replay) {
+    _replay = replay;
+  }
+
+  /// 重新执行上一次搜索（分页加载更多时调用）。
+  void replayLastSearch() => _replay?.call();
+}
+
+/// 轻量级 Web 异步搜索栏，替代已停维的 `flappy_search_bar` 的 `SearchBar`。
+///
+/// 基本流程：输入达到 [minimumChars] 个字符后，调用 [onSearch] 取结果，
+/// 用 [onItemFound] 渲染每一条；无结果时显示 [emptyWidget]；出错显示 [onError]。
+///
+/// 注意：`searchBarController` 参数刻意使用裸类型（`SearchBarController?`），
+/// 以兼容调用方 `SearchBarController _controller = SearchBarController<Product>();`
+/// 的写法（Dart 3 sound 类型下避免泛型不变性报错）。
+class SearchBar<T> extends StatefulWidget {
+  final SearchBarController? searchBarController;
+  final int minimumChars;
+  final String? hintText;
+  final Widget? cancellationWidget;
+  final Future<List<T>> Function(String text) onSearch;
+  final Widget Function(T item, int index) onItemFound;
+  final Widget Function(dynamic error)? onError;
+  final Widget? emptyWidget;
+  final Duration debounceDuration;
+
+  const SearchBar({
+    super.key,
+    this.searchBarController,
+    this.minimumChars = 2,
+    this.hintText,
+    this.cancellationWidget,
+    required this.onSearch,
+    required this.onItemFound,
+    this.onError,
+    this.emptyWidget,
+    this.debounceDuration = const Duration(milliseconds: 350),
+  });
+
+  @override
+  State<SearchBar<T>> createState() => _SearchBarState<T>();
+}
+
+class _SearchBarState<T> extends State<SearchBar<T>> {
+  final TextEditingController _textController = TextEditingController();
+  final FocusNode _focusNode = FocusNode();
+  Timer? _debounce;
+  List<T> _results = <T>[];
+  bool _loading = false;
+  dynamic _error;
+  bool _hasSearched = false;
+
+  @override
+  void initState() {
+    super.initState();
+    widget.searchBarController?._register(_runSearch);
+    _textController.addListener(_onTextChanged);
+  }
+
+  @override
+  void dispose() {
+    _debounce?.cancel();
+    _textController.dispose();
+    _focusNode.dispose();
+    super.dispose();
+  }
+
+  void _onTextChanged() {
+    final text = _textController.text;
+    _debounce?.cancel();
+    if (text.length >= widget.minimumChars) {
+      _debounce = Timer(widget.debounceDuration, _runSearch);
+    } else if (text.isEmpty) {
+      setState(() {
+        _results = <T>[];
+        _hasSearched = false;
+        _error = null;
+      });
+    }
+  }
+
+  Future<void> _runSearch() async {
+    final query = _textController.text;
+    if (query.length < widget.minimumChars) return;
+    if (widget.searchBarController != null) {
+      widget.searchBarController!.lastQuery = query;
+    }
+    setState(() {
+      _loading = true;
+      _error = null;
+      _hasSearched = true;
+    });
+    try {
+      final results = await widget.onSearch(query);
+      if (mounted) {
+        setState(() {
+          _results = results;
+          _loading = false;
+        });
+      }
+    } catch (e) {
+      if (mounted) {
+        setState(() {
+          _error = e;
+          _loading = false;
+        });
+      }
+    }
+  }
+
+  void _cancel() {
+    _textController.clear();
+    _focusNode.unfocus();
+    setState(() {
+      _results = <T>[];
+      _hasSearched = false;
+      _error = null;
+    });
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    return Column(
+      children: <Widget>[
+        TextField(
+          controller: _textController,
+          focusNode: _focusNode,
+          decoration: InputDecoration(
+            hintText: widget.hintText,
+            prefixIcon: const Icon(Icons.search),
+            suffixIcon: _textController.text.isNotEmpty
+                ? GestureDetector(
+                    onTap: _cancel,
+                    child: widget.cancellationWidget ??
+                        const Icon(Icons.close, size: 20),
+                  )
+                : null,
+            border: OutlineInputBorder(
+              borderRadius: BorderRadius.circular(8),
+            ),
+            contentPadding: const EdgeInsets.symmetric(horizontal: 12),
+          ),
+        ),
+        const SizedBox(height: 8),
+        Expanded(child: _buildBody()),
+      ],
+    );
+  }
+
+  Widget _buildBody() {
+    if (_loading) {
+      return const Center(child: CircularProgressIndicator());
+    }
+    if (_error != null) {
+      return widget.onError != null
+          ? widget.onError!(_error)
+          : Center(child: Text('$_error'));
+    }
+    if (!_hasSearched) {
+      return const SizedBox.shrink();
+    }
+    if (_results.isEmpty) {
+      return widget.emptyWidget ?? const SizedBox.shrink();
+    }
+    return ListView.builder(
+      itemCount: _results.length,
+      itemBuilder: (BuildContext context, int index) =>
+          widget.onItemFound(_results[index], index),
+    );
+  }
+}

lib/widgets/general/smooth_star_rating.dart

@@ -0,0 +1,90 @@
+import 'package:flutter/material.dart';
+
+/// 自定义实现，替代已停维的 `smooth_star_rating` 包的 [SmoothStarRating]。
+///
+/// 保留原命名参数（`allowHalfRating`/`onRated`/`starCount`/`rating`/`size`/
+/// `filledIconData`/`color`/`borderColor`/`spacing`），调用方仅改 import 即可。
+class SmoothStarRating extends StatefulWidget {
+  final bool allowHalfRating;
+  final void Function(double)? onRated;
+  final int starCount;
+  final double rating;
+  final double size;
+  final IconData filledIconData;
+  final IconData? halfFilledIconData;
+  final IconData? defaultIconData;
+  final Color color;
+  final Color borderColor;
+  final double spacing;
+
+  const SmoothStarRating({
+    super.key,
+    this.allowHalfRating = false,
+    this.onRated,
+    this.starCount = 5,
+    this.rating = 0.0,
+    this.size = 24.0,
+    this.filledIconData = Icons.star,
+    this.halfFilledIconData,
+    this.defaultIconData,
+    this.color = Colors.orange,
+    this.borderColor = Colors.orange,
+    this.spacing = 0.0,
+  });
+
+  @override
+  State<SmoothStarRating> createState() => _SmoothStarRatingState();
+}
+
+class _SmoothStarRatingState extends State<SmoothStarRating> {
+  late double _rating;
+
+  @override
+  void initState() {
+    super.initState();
+    _rating = widget.rating;
+  }
+
+  @override
+  void didUpdateWidget(covariant SmoothStarRating oldWidget) {
+    super.didUpdateWidget(oldWidget);
+    if (oldWidget.rating != widget.rating) {
+      _rating = widget.rating;
+    }
+  }
+
+  Widget _star(int index) {
+    IconData icon;
+    Color iconColor;
+    if (index < _rating.floor()) {
+      icon = widget.filledIconData;
+      iconColor = widget.color;
+    } else if (widget.allowHalfRating &&
+        index == _rating.floor() &&
+        (_rating - index) >= 0.5) {
+      icon = widget.halfFilledIconData ?? Icons.star_half;
+      iconColor = widget.color;
+    } else {
+      icon = widget.defaultIconData ?? Icons.star_border;
+      iconColor = widget.borderColor;
+    }
+    return GestureDetector(
+      onTap: () {
+        setState(() => _rating = (index + 1).toDouble());
+        widget.onRated?.call(_rating);
+      },
+      child: Padding(
+        padding: EdgeInsets.symmetric(horizontal: widget.spacing / 2),
+        child: Icon(icon, size: widget.size, color: iconColor),
+      ),
+    );
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    return Row(
+      mainAxisSize: MainAxisSize.min,
+      children: List<Widget>.generate(widget.starCount, _star),
+    );
+  }
+}

lib/widgets/general/text_link.dart

@@ -3,7 +3,7 @@ import 'package:fluro/fluro.dart';
 import 'package:flutter/material.dart';
 import 'package:flutter/rendering.dart';
 import 'package:flutter_wisetronic/utils/utils.dart';
-import 'package:hovering/hovering.dart';
+import 'hover_widget.dart';
 import 'package:url_launcher/url_launcher.dart';
 
 import '../../routes.dart';