feat: 用药打卡全面重构 - 按次追踪 + 独立打卡页 + 任务区汇总

- 后端用药提醒改为按次粒度(每个服药时间独立判断)
- 新增 per-dose 打卡/取消打卡 API
- 新增 MedicationCheckInPage 独立打卡页(每药每时间单独toggle)
- 用药列表删底部弹窗(编辑/停药),点药品直接进该药打卡页
- 任务区用药汇总为一行(过期待服已服)
- 支持隔天(EveryOtherDay)/每周频率判断
- 删历史对话功能(ConversationItem + conversationListProvider + UI)

health_app/pubspec.lock

@@ -238,6 +238,11 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "6.0.0"
+  flutter_localizations:
+    dependency: "direct main"
+    description: flutter
+    source: sdk
+    version: "0.0.0"
   flutter_markdown:
     dependency: "direct main"
     description:
@@ -376,6 +381,14 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "0.2.2"
+  intl:
+    dependency: transitive
+    description:
+      name: intl
+      sha256: "3df61194eb431efc39c4ceba583b95633a403f46c9fd341e550ce0bfa50e9aa5"
+      url: "https://pub.dev"
+    source: hosted
+    version: "0.20.2"
   io:
     dependency: transitive
     description: