fix: diet capture flow - 去掉多余页面，点击直接拍照

- 点击"拍照识别/上传照片"直接打开相机/相册，不再跳转多余选择页
- DietCapturePage 去掉重复的拍照按钮，只保留分析结果展示
- 新增 dietActionProvider 处理拍饮食触发
- 修复 initState reset 导致结果页被清空的 bug
- 修复 IP 地址恢复问题

health_app/lib/pages/home/home_page.dart

@@ -6,6 +6,7 @@ import 'dart:io';
 import '../../providers/auth_provider.dart';
 import '../../providers/chat_provider.dart';
 import '../../providers/data_providers.dart';
+import '../diet/diet_capture_page.dart';
 import '../../core/navigation_provider.dart';
 import '../../widgets/health_drawer.dart';
 import 'widgets/chat_messages_view.dart';
@@ -53,6 +54,16 @@ class _HomePageState extends ConsumerState<HomePage> {
       }
     });
 
+    ref.listen(dietActionProvider, (prev, next) {
+      if (next == 'pickFoodCamera') {
+        _pickFoodImage(ImageSource.camera);
+        ref.read(dietActionProvider.notifier).clear();
+      } else if (next == 'pickFoodGallery') {
+        _pickFoodImage(ImageSource.gallery);
+        ref.read(dietActionProvider.notifier).clear();
+      }
+    });
+
     return Scaffold(
       drawer: const HealthDrawer(),
       backgroundColor: const Color(0xFFF8F9FC),
@@ -217,6 +228,17 @@ class _HomePageState extends ConsumerState<HomePage> {
     }
   }
 
+  Future<void> _pickFoodImage(ImageSource source) async {
+    final picker = ImagePicker();
+    final picked = await picker.pickImage(source: source, imageQuality: 80, maxWidth: 1024, maxHeight: 1024);
+    if (picked != null && mounted) {
+      ref.read(dietProvider.notifier).reset();
+      ref.read(dietProvider.notifier).setImage(picked.path);
+      ref.read(dietProvider.notifier).analyzeImage();
+      pushRoute(ref, 'dietCapture');
+    }
+  }
+
   void _showAttachmentPicker(BuildContext context) {
     showModalBottomSheet(context: context, builder: (ctx) => SafeArea(child: Wrap(children: [
       ListTile(leading: const Icon(Icons.camera_alt), title: const Text('拍照'), onTap: () { Navigator.pop(ctx); _pickImage(ImageSource.camera); }),