feat(app): 预种计划三按钮合并为单入口 Hub 页面

## 背景
「我」页面原有三个并排的预种按钮（预种购买 / 预种明细 / 团队预种），
三等分宽度导致文字拥挤，视觉层级也不清晰。

## 改动内容

### 新增文件
- `pre_planting_hub_page.dart`
  预种计划 Hub 汇总页，竖排展示三个功能入口卡片：
  · 预种购买（金色）→ /pre-planting/purchase
  · 预种明细（棕色）→ /pre-planting/position
  · 团队预种（绿色）→ /pre-planting/team
  页面为纯导航页，无需加载数据；风格与 pre_planting_purchase_page
  一致（渐变背景、金色「← 返回」Header、Inter 字体）。

### 修改文件
- `route_paths.dart` / `route_names.dart`
  新增路由常量 prePlantingHub = '/pre-planting/hub'

- `app_router.dart`
  注册 GoRoute(path: prePlantingHub) → PrePlantingHubPage
  新增对应 import

- `profile_page.dart`
  · 删除 `_buildPrePlantingButtons()`（三按钮并排 Widget）
  · 删除已无用的三个导航方法：
    _goToPrePlantingPurchase / _goToPrePlantingPosition / _goToTeamPrePlanting
  · 新增 `_buildPrePlantingEntryButton()`：
    满宽 48px 按钮，文字「申请预种计划」，点击跳转 Hub 页
  · 布局调用处改为 _buildPrePlantingEntryButton()

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

frontend/mobile-app/lib/features/pre_planting/presentation/pages/pre_planting_hub_page.dart

@@ -0,0 +1,191 @@
+import 'package:flutter/material.dart';
+import 'package:go_router/go_router.dart';
+import '../../../../routes/route_paths.dart';
+
+/// [2026-03-04] 预种计划 Hub 页面
+///
+/// 作为「我」页面「申请预种计划」按钮的下级页面，
+/// 汇总展示预种三大功能入口：预种购买、预种明细、团队预种。
+class PrePlantingHubPage extends StatelessWidget {
+  const PrePlantingHubPage({super.key});
+
+  @override
+  Widget build(BuildContext context) {
+    return Scaffold(
+      body: Container(
+        decoration: const BoxDecoration(
+          gradient: LinearGradient(
+            begin: Alignment.topCenter,
+            end: Alignment.bottomCenter,
+            colors: [Color(0xFFFFF7E6), Color(0xFFEAE0C8)],
+          ),
+        ),
+        child: SafeArea(
+          child: Column(
+            children: [
+              _buildHeader(context),
+              Expanded(
+                child: Padding(
+                  padding: const EdgeInsets.all(16),
+                  child: Column(
+                    children: [
+                      const SizedBox(height: 8),
+                      _buildEntryCard(
+                        context,
+                        icon: Icons.add_circle_outline,
+                        color: const Color(0xFFD4AF37),
+                        title: '预种购买',
+                        subtitle: '购买预种份额，累计 10 份合成 1 棵树',
+                        onTap: () => context.push(RoutePaths.prePlantingPurchase),
+                      ),
+                      const SizedBox(height: 12),
+                      _buildEntryCard(
+                        context,
+                        icon: Icons.account_balance_wallet_outlined,
+                        color: const Color(0xFF5D4037),
+                        title: '预种明细',
+                        subtitle: '查看预种订单和合并记录',
+                        onTap: () => context.push(RoutePaths.prePlantingPosition),
+                      ),
+                      const SizedBox(height: 12),
+                      _buildEntryCard(
+                        context,
+                        icon: Icons.groups_outlined,
+                        color: const Color(0xFF2E7D32),
+                        title: '团队预种',
+                        subtitle: '查看个人与团队预种统计',
+                        onTap: () => context.push(RoutePaths.teamPrePlanting),
+                      ),
+                    ],
+                  ),
+                ),
+              ),
+            ],
+          ),
+        ),
+      ),
+    );
+  }
+
+  Widget _buildHeader(BuildContext context) {
+    return Container(
+      padding: const EdgeInsets.symmetric(horizontal: 16, vertical: 8),
+      decoration: BoxDecoration(
+        color: const Color(0xFFFFF7E6).withValues(alpha: 0.8),
+      ),
+      child: Row(
+        children: [
+          GestureDetector(
+            onTap: () => context.pop(),
+            child: Container(
+              width: 32,
+              height: 32,
+              alignment: Alignment.center,
+              child: const Icon(
+                Icons.arrow_back_ios,
+                color: Color(0xFFD4AF37),
+                size: 20,
+              ),
+            ),
+          ),
+          const SizedBox(width: 4),
+          GestureDetector(
+            onTap: () => context.pop(),
+            child: const Text(
+              '返回',
+              style: TextStyle(
+                fontSize: 16,
+                fontFamily: 'Inter',
+                height: 1.5,
+                color: Color(0xFFD4AF37),
+              ),
+            ),
+          ),
+          const SizedBox(width: 42),
+          const Expanded(
+            child: Text(
+              '预种计划',
+              style: TextStyle(
+                fontSize: 18,
+                fontFamily: 'Inter',
+                fontWeight: FontWeight.w700,
+                height: 1.25,
+                letterSpacing: -0.27,
+                color: Color(0xFF5D4037),
+              ),
+            ),
+          ),
+        ],
+      ),
+    );
+  }
+
+  Widget _buildEntryCard(
+    BuildContext context, {
+    required IconData icon,
+    required Color color,
+    required String title,
+    required String subtitle,
+    required VoidCallback onTap,
+  }) {
+    return GestureDetector(
+      onTap: onTap,
+      child: Container(
+        width: double.infinity,
+        padding: const EdgeInsets.symmetric(horizontal: 16, vertical: 18),
+        decoration: BoxDecoration(
+          color: Colors.white.withValues(alpha: 0.85),
+          borderRadius: BorderRadius.circular(12),
+          border: Border.all(
+            color: color.withValues(alpha: 0.25),
+            width: 1,
+          ),
+        ),
+        child: Row(
+          children: [
+            Container(
+              width: 48,
+              height: 48,
+              decoration: BoxDecoration(
+                color: color.withValues(alpha: 0.12),
+                borderRadius: BorderRadius.circular(12),
+              ),
+              child: Icon(icon, color: color, size: 24),
+            ),
+            const SizedBox(width: 16),
+            Expanded(
+              child: Column(
+                crossAxisAlignment: CrossAxisAlignment.start,
+                children: [
+                  Text(
+                    title,
+                    style: TextStyle(
+                      fontSize: 16,
+                      fontFamily: 'Inter',
+                      fontWeight: FontWeight.w600,
+                      color: color,
+                    ),
+                  ),
+                  const SizedBox(height: 4),
+                  Text(
+                    subtitle,
+                    style: const TextStyle(
+                      fontSize: 13,
+                      fontFamily: 'Inter',
+                      color: Color(0xFF8D6E63),
+                    ),
+                  ),
+                ],
+              ),
+            ),
+            Icon(
+              Icons.chevron_right,
+              color: color.withValues(alpha: 0.6),
+              size: 20,
+            ),
+          ],
+        ),
+      ),
+    );
+  }
+}

frontend/mobile-app/lib/features/profile/presentation/pages/profile_page.dart

@@ -1356,16 +1356,6 @@ class _ProfilePageState extends ConsumerState<ProfilePage> {
     }
   }
 
-  /// [2026-02-17] 进入预种计划购买页
-  void _goToPrePlantingPurchase() {
-    context.push(RoutePaths.prePlantingPurchase);
-  }
-
-  /// [2026-02-17] 进入预种持仓页
-  void _goToPrePlantingPosition() {
-    context.push(RoutePaths.prePlantingPosition);
-  }
-
   /// 谷歌验证器
   void _goToGoogleAuth() {
     context.push(RoutePaths.googleAuth);
@@ -1551,10 +1541,10 @@ class _ProfilePageState extends ConsumerState<ProfilePage> {
                     // 认种按钮
                     _buildPlantingButton(),
                     const SizedBox(height: 8),
-                    // [2026-02-17] 预种计划按钮（购买 + 查看持仓）
+                    // [2026-03-04] 预种计划入口（三功能合并为单按钮）
                     // 仅在后台管理端预种开关开启时显示
                     if (_isPrePlantingActive) ...[
-                      _buildPrePlantingButtons(),
+                      _buildPrePlantingEntryButton(),
                       const SizedBox(height: 8),
                     ],
                     const SizedBox(height: 16),
@@ -2041,20 +2031,13 @@ class _ProfilePageState extends ConsumerState<ProfilePage> {
     );
   }
 
-  /// [2026-02-17] 构建预种计划按钮行（购买 + 查看持仓）
+  /// [2026-03-04] 构建预种计划入口按钮（原三按钮合并为一个）
-  ///
+  Widget _buildPrePlantingEntryButton() {
-  /// 两个按钮并排显示：
+    return GestureDetector(
-  /// - 左侧「预种购买」：跳转到预种购买页（选择份数 → 支付 1887 USDT/份）
+      onTap: () => context.push(RoutePaths.prePlantingHub),
-  /// - 右侧「预种持仓」：跳转到预种持仓页（查看订单、合并记录、签约）
-  Widget _buildPrePlantingButtons() {
-    return Row(
-      children: [
-        // 预种购买按钮
-        Expanded(
-          child: GestureDetector(
-            onTap: _goToPrePlantingPurchase,
       child: Container(
-              height: 44,
+        width: double.infinity,
+        height: 48,
         decoration: BoxDecoration(
           color: const Color(0xFFD4AF37).withValues(alpha: 0.15),
           borderRadius: BorderRadius.circular(8),
@@ -2066,111 +2049,25 @@ class _ProfilePageState extends ConsumerState<ProfilePage> {
         child: const Row(
           mainAxisAlignment: MainAxisAlignment.center,
           children: [
-                  Icon(
+            Icon(Icons.eco_outlined, color: Color(0xFFD4AF37), size: 20),
-                    Icons.add_circle_outline,
+            SizedBox(width: 8),
-                    color: Color(0xFFD4AF37),
-                    size: 18,
-                  ),
-                  SizedBox(width: 6),
             Text(
-                    '预种购买',
+              '申请预种计划',
               style: TextStyle(
-                      fontSize: 14,
+                fontSize: 15,
                 fontFamily: 'Inter',
                 fontWeight: FontWeight.w600,
                 color: Color(0xFFD4AF37),
               ),
             ),
+            SizedBox(width: 4),
+            Icon(Icons.chevron_right, color: Color(0xFFD4AF37), size: 18),
           ],
         ),
       ),
-          ),
-        ),
-        const SizedBox(width: 8),
-        // 预种持仓按钮
-        Expanded(
-          child: GestureDetector(
-            onTap: _goToPrePlantingPosition,
-            child: Container(
-              height: 44,
-              decoration: BoxDecoration(
-                color: const Color(0xFF5D4037).withValues(alpha: 0.08),
-                borderRadius: BorderRadius.circular(8),
-                border: Border.all(
-                  color: const Color(0xFF5D4037).withValues(alpha: 0.2),
-                  width: 1,
-                ),
-              ),
-              child: const Row(
-                mainAxisAlignment: MainAxisAlignment.center,
-                children: [
-                  Icon(
-                    Icons.account_balance_wallet_outlined,
-                    color: Color(0xFF5D4037),
-                    size: 18,
-                  ),
-                  SizedBox(width: 6),
-                  Text(
-                    '预种明细',
-                    style: TextStyle(
-                      fontSize: 14,
-                      fontFamily: 'Inter',
-                      fontWeight: FontWeight.w600,
-                      color: Color(0xFF5D4037),
-                    ),
-                  ),
-                ],
-              ),
-            ),
-          ),
-        ),
-        const SizedBox(width: 8),
-        // [2026-03-02] 团队预种按钮（功能6）
-        Expanded(
-          child: GestureDetector(
-            onTap: _goToTeamPrePlanting,
-            child: Container(
-              height: 44,
-              decoration: BoxDecoration(
-                color: const Color(0xFF2E7D32).withValues(alpha: 0.08),
-                borderRadius: BorderRadius.circular(8),
-                border: Border.all(
-                  color: const Color(0xFF2E7D32).withValues(alpha: 0.2),
-                  width: 1,
-                ),
-              ),
-              child: const Row(
-                mainAxisAlignment: MainAxisAlignment.center,
-                children: [
-                  Icon(
-                    Icons.groups_outlined,
-                    color: Color(0xFF2E7D32),
-                    size: 18,
-                  ),
-                  SizedBox(width: 6),
-                  Text(
-                    '团队预种',
-                    style: TextStyle(
-                      fontSize: 14,
-                      fontFamily: 'Inter',
-                      fontWeight: FontWeight.w600,
-                      color: Color(0xFF2E7D32),
-                    ),
-                  ),
-                ],
-              ),
-            ),
-          ),
-        ),
-      ],
     );
   }
 
-  /// [2026-03-02] 进入团队预种页（功能6）
-  void _goToTeamPrePlanting() {
-    context.push(RoutePaths.teamPrePlanting);
-  }
-
   /// 构建主要内容卡片
   Widget _buildMainContentCard() {
     // Widget 结构始终保持，数据值根据状态显示 "0" 或实际值

frontend/mobile-app/lib/routes/app_router.dart

@@ -45,6 +45,7 @@ import '../features/contract_signing/presentation/pages/contract_signing_page.da
 import '../features/contract_signing/presentation/pages/pending_contracts_page.dart';
 import '../features/pending_actions/presentation/pages/pending_actions_page.dart';
 // [2026-02-17] 新增：预种计划页面（1887 USDT/份，累计 10 份合成 1 棵树）
+import '../features/pre_planting/presentation/pages/pre_planting_hub_page.dart';
 import '../features/pre_planting/presentation/pages/pre_planting_purchase_page.dart';
 import '../features/pre_planting/presentation/pages/pre_planting_position_page.dart';
 import '../features/pre_planting/presentation/pages/pre_planting_merge_detail_page.dart';
@@ -445,6 +446,13 @@ final appRouterProvider = Provider<GoRouter>((ref) {
         builder: (context, state) => const ChangePhonePage(),
       ),
 
+      // [2026-03-04] Pre-Planting Hub Page (预种计划 - 入口汇总)
+      GoRoute(
+        path: RoutePaths.prePlantingHub,
+        name: RouteNames.prePlantingHub,
+        builder: (context, state) => const PrePlantingHubPage(),
+      ),
+
       // [2026-02-17] Pre-Planting Purchase Page (预种计划 - 购买页)
       GoRoute(
         path: RoutePaths.prePlantingPurchase,

frontend/mobile-app/lib/routes/route_names.dart

@@ -56,6 +56,7 @@ class RouteNames {
   static const changePhone = 'change-phone';
 
   // [2026-02-17] Pre-Planting (预种计划)
+  static const prePlantingHub = 'pre-planting-hub';             // [2026-03-04] Hub 汇总入口页
   static const prePlantingPurchase = 'pre-planting-purchase';   // 购买页
   static const prePlantingPosition = 'pre-planting-position';   // 持仓页
   static const prePlantingMergeDetail = 'pre-planting-merge';         // 合并详情页

frontend/mobile-app/lib/routes/route_paths.dart

@@ -56,6 +56,7 @@ class RoutePaths {
   static const changePhone = '/kyc/change-phone';
 
   // [2026-02-17] Pre-Planting (预种计划)
+  static const prePlantingHub = '/pre-planting/hub';                 // [2026-03-04] Hub 汇总入口页
   static const prePlantingPurchase = '/pre-planting/purchase';       // 购买页
   static const prePlantingPosition = '/pre-planting/position';       // 持仓页
   static const prePlantingMergeDetail = '/pre-planting/merge';       // 合并详情页