fix: 食物识别编辑框删除bug + VLM相关代码回滚

- 修复饮食识别结果编辑框一次只能删一个字的bug(控制器缓存)
- 回滚VLM图片压缩代码到原始状态
- 保持原有显示逻辑不变

health_app/lib/pages/diet/diet_capture_page.dart

@@ -593,6 +593,7 @@ class _DietCapturePageState extends ConsumerState<DietCapturePage> {
                   (v) => ref
                       .read(dietProvider.notifier)
                       .updateFoodName(food.id, v),
+                  fieldKey: '${food.id}_name',
                   style: const TextStyle(
                     fontSize: 17,
                     fontWeight: FontWeight.w600,
@@ -608,6 +609,7 @@ class _DietCapturePageState extends ConsumerState<DietCapturePage> {
                         (v) => ref
                             .read(dietProvider.notifier)
                             .updateFoodPortion(food.id, v),
+                        fieldKey: '${food.id}_portion',
                         hint: '份量',
                         style: const TextStyle(
                           fontSize: 14,
@@ -629,6 +631,7 @@ class _DietCapturePageState extends ConsumerState<DietCapturePage> {
                                     food.id,
                                     int.tryParse(v) ?? 0,
                                   ),
+                              fieldKey: '${food.id}_cal',
                               hint: '0',
                               style: const TextStyle(
                                 fontSize: 14,
@@ -664,16 +667,26 @@ class _DietCapturePageState extends ConsumerState<DietCapturePage> {
     );
   }
 
+  final Map<String, TextEditingController> _fieldCtrls = {};
+
+  TextEditingController _ctrlFor(String key, String value) {
+    if (_fieldCtrls.containsKey(key)) return _fieldCtrls[key]!;
+    final c = TextEditingController(text: value);
+    _fieldCtrls[key] = c;
+    return c;
+  }
+
   Widget _compactField(
     String value,
     ValueChanged<String> cb, {
+    required String fieldKey,
     String? hint,
     TextStyle? style,
     TextAlign align = TextAlign.start,
     TextInputType? keyboardType,
   }) {
     return TextField(
-      controller: TextEditingController(text: value),
+      controller: _ctrlFor(fieldKey, value),
       onChanged: cb,
       keyboardType: keyboardType,
       textAlign: align,

health_app/lib/pages/home/widgets/chat_messages_view.dart

@@ -1245,47 +1245,11 @@ class ChatMessagesView extends ConsumerWidget {
     ChatMessage msg,
     WidgetRef ref,
   ) {
-    return StatefulBuilder(
-      builder: (context, setState) {
-        final controller = TextEditingController(text: field.value);
-        return TextField(
-          controller: controller,
-          autofocus: true,
-          style: const TextStyle(
-            fontSize: 18,
-            fontWeight: FontWeight.w600,
-            color: AppColors.textPrimary,
-          ),
-          decoration: InputDecoration(
-            contentPadding: const EdgeInsets.symmetric(
-              horizontal: 12,
-              vertical: 8,
-            ),
-            filled: true,
-            fillColor: Colors.white,
-            enabledBorder: OutlineInputBorder(
-              borderRadius: BorderRadius.circular(8),
-              borderSide: BorderSide(color: AppColors.primary.withAlpha(80)),
-            ),
-            focusedBorder: OutlineInputBorder(
-              borderRadius: BorderRadius.circular(8),
-              borderSide: const BorderSide(
-                color: AppColors.primary,
-                width: 1.5,
-              ),
-            ),
-          ),
-          onSubmitted: (value) {
-            ref
-                .read(chatProvider.notifier)
-                .finishEditingField(msg.id, field.label, value);
-          },
-          onTapOutside: (_) {
-            ref
-                .read(chatProvider.notifier)
-                .finishEditingField(msg.id, field.label, controller.text);
-          },
-        );
+    return _EditFieldCell(
+      key: ValueKey('editing_${msg.id}_${field.label}'),
+      initialValue: field.value,
+      onDone: (value) {
+        ref.read(chatProvider.notifier).finishEditingField(msg.id, field.label, value);
       },
     );
   }
@@ -2478,3 +2442,36 @@ class _ExpandableAdviceState extends State<_ExpandableAdvice> {
     );
   }
 }
+
+class _EditFieldCell extends StatefulWidget {
+  final String initialValue;
+  final ValueChanged<String> onDone;
+  const _EditFieldCell({super.key, required this.initialValue, required this.onDone});
+
+  @override State<_EditFieldCell> createState() => _EditFieldCellState();
+}
+
+class _EditFieldCellState extends State<_EditFieldCell> {
+  late final TextEditingController _ctrl;
+
+  @override void initState() {
+    super.initState();
+    _ctrl = TextEditingController(text: widget.initialValue);
+  }
+
+  @override void dispose() { _ctrl.dispose(); super.dispose(); }
+
+  @override Widget build(BuildContext context) => TextField(
+    controller: _ctrl,
+    autofocus: true,
+    style: const TextStyle(fontSize: 18, fontWeight: FontWeight.w600, color: Color(0xFF1E293B)),
+    decoration: InputDecoration(
+      contentPadding: const EdgeInsets.symmetric(horizontal: 12, vertical: 8),
+      filled: true, fillColor: Colors.white,
+      enabledBorder: OutlineInputBorder(borderRadius: BorderRadius.circular(8), borderSide: BorderSide(color: const Color(0xFF6366F1).withAlpha(80))),
+      focusedBorder: OutlineInputBorder(borderRadius: BorderRadius.circular(8), borderSide: const BorderSide(color: Color(0xFF6366F1), width: 1.5)),
+    ),
+    onSubmitted: widget.onDone,
+    onTapOutside: (_) => widget.onDone(_ctrl.text),
+  );
+}