feat: UI清爽紫蓝风全面改造 + 对话卡片重构 + 配色体系升级

- 新增 AppColors 统一配色方案（清爽紫蓝，参考蚂蚁阿福风格）
- 新增 common_widgets（GradientBorderButton / CardActionButton / IconBox）
- AgentWelcomeCard 美化：渐变 header + AI标签 + 核心功能区 + 快捷操作区
- DataConfirmCard 统一：三合一（健康/药品/运动），可编辑字段列表
- 删除死代码：medicationConfirm/dietAnalysis/reportAnalysis/quickOptions 卡片
- 删除死路由：doctors/profileEdit/editProfile
- AI 对话去除 Markdown 符号（_stripMd），统一行间距 1.5
- 逐字淡入动画修复：key 改用 stableId 避免重复触发
- 健康概览时间修复：前端发送 UTC 避免时区歧义
- PG 数据目录迁入项目 backend/pgdata/，加入 .gitignore
- 新增欧姆龙血压计实施方案文档

health_app/lib/widgets/common_widgets.dart

@@ -0,0 +1,136 @@
+import 'package:flutter/material.dart';
+import '../core/app_colors.dart';
+
+/// 渐变边框按钮（白色底+彩色渐变边框）
+class GradientBorderButton extends StatelessWidget {
+  final String text;
+  final IconData? icon;
+  final VoidCallback? onTap;
+  final double height;
+  final bool isSuccess;
+
+  const GradientBorderButton({
+    super.key,
+    required this.text,
+    this.icon,
+    this.onTap,
+    this.height = 52,
+    this.isSuccess = false,
+  });
+
+  @override
+  Widget build(BuildContext context) {
+    return Container(
+      height: height,
+      decoration: BoxDecoration(
+        gradient: isSuccess ? AppColors.successButtonGradient : AppColors.buttonGradient,
+        borderRadius: BorderRadius.circular(14),
+        boxShadow: AppColors.buttonShadow,
+      ),
+      child: Material(
+        color: Colors.transparent,
+        child: InkWell(
+          onTap: onTap,
+          borderRadius: BorderRadius.circular(14),
+          child: Row(
+            mainAxisAlignment: MainAxisAlignment.center,
+            children: [
+              if (icon != null) ...[
+                Icon(icon, size: 22, color: AppColors.textOnGradient),
+                const SizedBox(width: 8),
+              ],
+              Text(
+                text,
+                style: const TextStyle(
+                  fontSize: 17,
+                  fontWeight: FontWeight.w600,
+                  color: AppColors.textOnGradient,
+                ),
+              ),
+            ],
+          ),
+        ),
+      ),
+    );
+  }
+}
+
+/// 卡片内的小操作按钮
+class CardActionButton extends StatelessWidget {
+  final String label;
+  final IconData icon;
+  final VoidCallback? onTap;
+  final Color? iconColor;
+
+  const CardActionButton({
+    super.key,
+    required this.label,
+    required this.icon,
+    this.onTap,
+    this.iconColor,
+  });
+
+  @override
+  Widget build(BuildContext context) {
+    return InkWell(
+      onTap: onTap,
+      borderRadius: BorderRadius.circular(12),
+      child: Container(
+        padding: const EdgeInsets.symmetric(horizontal: 14, vertical: 10),
+        decoration: BoxDecoration(
+          color: AppColors.backgroundSecondary,
+          borderRadius: BorderRadius.circular(12),
+          border: Border.all(color: AppColors.borderLight),
+        ),
+        child: Row(
+          mainAxisSize: MainAxisSize.min,
+          children: [
+            Icon(icon, size: 18, color: iconColor ?? AppColors.iconColor),
+            const SizedBox(width: 6),
+            Text(
+              label,
+              style: TextStyle(
+                fontSize: 14,
+                fontWeight: FontWeight.w500,
+                color: AppColors.textPrimary,
+              ),
+            ),
+          ],
+        ),
+      ),
+    );
+  }
+}
+
+/// 功能区小图标容器
+class IconBox extends StatelessWidget {
+  final IconData icon;
+  final double size;
+  final Color? backgroundColor;
+  final Color? iconColor;
+
+  const IconBox({
+    super.key,
+    required this.icon,
+    this.size = 44,
+    this.backgroundColor,
+    this.iconColor,
+  });
+
+  @override
+  Widget build(BuildContext context) {
+    return Container(
+      width: size,
+      height: size,
+      decoration: BoxDecoration(
+        color: backgroundColor ?? AppColors.iconBackground,
+        borderRadius: BorderRadius.circular(size / 3),
+      ),
+      child: Icon(
+        icon,
+        size: size * 0.55,
+        color: iconColor ?? AppColors.iconColor,
+      ),
+    );
+  }
+}