feat: 三端抽屉重构 + 配色系统更新 + 后台管理页精调 + 键盘抬起组件

## 抽屉重构
- admin_drawer / doctor_drawer / health_drawer 三端抽屉全部重做
- drawer_shell 增强

## 配色系统
- app_colors / app_module_visuals / app_theme 更新
- app.dart 启动流程调整

## 后台管理页
- admin_doctors_page 大幅重构(+251)
- admin_home / doctor_dashboard / doctor_reports / doctor_home / doctor_followups / doctor_settings 精调

## 患者端
- home_page / chat_messages_view / medication_list / notification_center / remaining_pages / exercise_plan / device / diet / consultation 微调

## 新增
- keyboard_lift.dart: 键盘抬起处理组件
- AGENTS.md: agent 指引文档

## 其他
- api_client IP 适配
- app_future_view 增强
- data_providers 调整
- secondary_page_visuals_test 更新

health_app/lib/widgets/health_drawer.dart

@@ -213,11 +213,7 @@ class _HealthDashboard extends StatelessWidget {
         onTap: () => pushRoute(ref, 'trend'),
       ),
       titleColor: Colors.white,
-      backgroundGradient: const LinearGradient(
-        begin: Alignment.topCenter,
-        end: Alignment.bottomCenter,
-        colors: [Color(0xFF89F7FE), Color(0xFF66A6FF)],
-      ),
+      backgroundPainter: const _HealthDashboardBackgroundPainter(),
       child: latestHealth.when(
         data: (data) => _DashboardMetrics(data: data, ref: ref),
         loading: () => const SizedBox(
@@ -392,7 +388,7 @@ class _NavigationSection extends StatelessWidget {
         colors: AppColors.medicationGradient.colors,
       ),
       _NavItem(
-        icon: LucideIcons.utensils,
+        icon: AppModuleVisuals.diet.icon,
         title: '饮食',
         route: 'dietRecords',
         colors: AppColors.dietGradient.colors,
@@ -476,6 +472,7 @@ class _NavTile extends StatelessWidget {
 
   @override
   Widget build(BuildContext context) {
+    final isDevice = item.route == 'devices';
     return InkWell(
       onTap: onTap,
       borderRadius: AppRadius.mdBorder,
@@ -488,12 +485,16 @@ class _NavTile extends StatelessWidget {
               width: 48,
               height: 48,
               decoration: BoxDecoration(
-                gradient: LinearGradient(
-                  begin: Alignment.topLeft,
-                  end: Alignment.bottomRight,
-                  colors: _colors,
-                ),
+                color: isDevice ? AppColors.device : null,
+                gradient: isDevice
+                    ? null
+                    : LinearGradient(
+                        begin: Alignment.topLeft,
+                        end: Alignment.bottomRight,
+                        colors: _colors,
+                      ),
                 borderRadius: AppRadius.mdBorder,
+                border: null,
                 boxShadow: [
                   BoxShadow(
                     color: _colors.last.withValues(alpha: 0.10),
@@ -567,60 +568,96 @@ class _Panel extends StatelessWidget {
   final String title;
   final Widget child;
   final Widget? trailing;
-  final LinearGradient? backgroundGradient;
+  final CustomPainter? backgroundPainter;
   final Color titleColor;
   const _Panel({
     required this.title,
     required this.child,
     this.trailing,
-    this.backgroundGradient,
+    this.backgroundPainter,
     this.titleColor = AppColors.textPrimary,
   });
 
   @override
   Widget build(BuildContext context) {
     return Container(
-      padding: const EdgeInsets.all(14),
+      clipBehavior: Clip.antiAlias,
       decoration: BoxDecoration(
-        gradient:
-            backgroundGradient ??
-            LinearGradient(
-              begin: Alignment.topLeft,
-              end: Alignment.bottomRight,
-              colors: [
-                Colors.white.withValues(alpha: 0.92),
-                const Color(0xFFF8F4FF).withValues(alpha: 0.84),
-              ],
-            ),
+        color: backgroundPainter == null ? null : const Color(0xFFBAE6FD),
+        gradient: backgroundPainter != null
+            ? null
+            : LinearGradient(
+                begin: Alignment.topLeft,
+                end: Alignment.bottomRight,
+                colors: [
+                  Colors.white.withValues(alpha: 0.92),
+                  const Color(0xFFF8F4FF).withValues(alpha: 0.84),
+                ],
+              ),
         borderRadius: AppRadius.xlBorder,
         boxShadow: AppShadows.soft,
       ),
-      child: Column(
-        crossAxisAlignment: CrossAxisAlignment.start,
-        children: [
-          Row(
+      child: CustomPaint(
+        painter: backgroundPainter,
+        child: Padding(
+          padding: const EdgeInsets.all(14),
+          child: Column(
+            crossAxisAlignment: CrossAxisAlignment.start,
             children: [
-              Expanded(
-                child: Text(
-                  title,
-                  style: TextStyle(
-                    fontSize: 18,
-                    fontWeight: FontWeight.w600,
-                    color: titleColor,
+              Row(
+                children: [
+                  Expanded(
+                    child: Text(
+                      title,
+                      style: TextStyle(
+                        fontSize: 18,
+                        fontWeight: FontWeight.w600,
+                        color: titleColor,
+                      ),
+                    ),
                   ),
-                ),
+                  ?trailing,
+                ],
               ),
-              ?trailing,
+              const SizedBox(height: 12),
+              child,
             ],
           ),
-          const SizedBox(height: 12),
-          child,
-        ],
+        ),
       ),
     );
   }
 }
 
+class _HealthDashboardBackgroundPainter extends CustomPainter {
+  const _HealthDashboardBackgroundPainter();
+
+  @override
+  void paint(Canvas canvas, Size size) {
+    final rect = Offset.zero & size;
+    canvas.drawRect(rect, Paint()..color = const Color(0xFFBAE6FD));
+
+    void drawGlow(Alignment center, Color color) {
+      final paint = Paint()
+        ..shader = RadialGradient(
+          center: center,
+          radius: 1,
+          colors: [color, color.withValues(alpha: 0)],
+          stops: const [0, 0.8],
+        ).createShader(rect);
+      canvas.drawRect(rect, paint);
+    }
+
+    drawGlow(Alignment.bottomRight, const Color(0xFF818CF8));
+    drawGlow(const Alignment(0, 0.6), const Color(0xFF60A5FA));
+    drawGlow(const Alignment(0.6, -0.6), const Color(0xFF6366F1));
+    drawGlow(const Alignment(-0.6, -0.6), const Color(0xFF38BDF8));
+  }
+
+  @override
+  bool shouldRepaint(_HealthDashboardBackgroundPainter oldDelegate) => false;
+}
+
 class _TextAction extends StatelessWidget {
   final String label;
   final VoidCallback onTap;