improve README architecture overview

Author: alvin000009238

README.md

@@ -19,9 +19,112 @@
 
 ```mermaid
 flowchart TB
-    App["Android App"] --> School["學校系統 API"]
+    subgraph Repo["Repo"]
+        Android["android/\nKotlin / Jetpack Compose / Material 3"]
+        Demo["demo/\n展示網站與截圖素材"]
+        Workflows[".github/workflows/\nrelease、demo deploy、CodeQL"]
+    end
+
+    subgraph AndroidApp["Android app: com.clhs.score"]
+        Main["MainActivity\n入口、deep link、FLAG_SECURE、生物識別鎖"]
+        AppShell["ScoreApp\nCompose NavHost 與全域狀態同步"]
+
+        subgraph UI["ui/"]
+            Login["WebViewLoginScreen\n學校登入與 cookie 回收"]
+            Grades["GradesScreen / Subject / Charts\n成績總覽、分析、趨勢、模擬器"]
+            ScheduleUi["schedule/ScheduleScreen\n課表查詢與 Widget 設定"]
+            SettingsUi["SettingsScreen\n主題、通知、更新、匯出、生物識別"]
+            LockUi["BiometricLockScreen\n指紋 / PIN 解鎖覆蓋層"]
+        end
+
+        subgraph ViewModels["viewmodel/"]
+            ScoreVm["ScoreViewModel\n登入、成績、比較、趨勢、匯出、段考提醒"]
+            ScheduleVm["ScheduleViewModel\n課表查詢與 Widget 偏好"]
+            SettingsVm["SettingsViewModel\n設定、通知 topic、更新檢查"]
+        end
+
+        subgraph Data["data/"]
+            GradeRepo["GradeRepository\nsession restore、cache-first 成績讀取"]
+            ScheduleRepo["ScheduleRepository\n課表年份、班級、課表內容"]
+            SchoolClient["SchoolGradeClient\nOkHttp + Jsoup + JSON parsing"]
+            CookieJar["SchoolCookieJar\n同步鎖保護 cookie 讀寫"]
+            Stores["SessionStore / GradeCacheStore / SettingsRepository\nDataStore、Security Crypto、本機快取"]
+            Analysis["GradeAnalysis / GradeReportDiffer\n分析、趨勢、可見資訊 diff"]
+            Exporter["GradeExporter\nMediaStore CSV 匯出"]
+            Biometric["BiometricHelper\nKeystore key wrapping"]
+            FakeData["FakeData\n-PuseFakeData / demo mode"]
+        end
+
+        subgraph Background["背景與系統整合"]
+            Reminder["GradeReminderWorker + Scheduler + Notifier\nWorkManager 15 分鐘週期檢查"]
+            Widget["ScheduleWidget + Receivers\nGlance widget 與 AlarmManager 更新"]
+            Fcm["ScoreFirebaseMessagingService + TopicManager\nFCM 通知與 topic 訂閱"]
+            Channels["NotificationChannels\nscore_updates / grade_reminders"]
+            FileProvider["FileProvider\nAPK 更新安裝與匯出分享 URI"]
+        end
+
+        subgraph Analytics["analytics/"]
+            Logger["AnalyticsLogger / FirebaseAnalyticsLogger\n集中匿名事件記錄"]
+            Sanitizer["AnalyticsParameterSanitizer\n白名單與敏感欄位防護"]
+        end
+    end
+
+    subgraph External["外部服務 / Android 系統"]
+        School["欣河智慧校園 / 學校系統\nhttps://shcloud2.k12ea.gov.tw/CLHSTYC"]
+        Firebase["Firebase\nAnalytics + Cloud Messaging"]
+        GitHub["GitHub Releases\n版本檢查與 APK 發布"]
+        AndroidSystem["Android System\n通知權限、Keystore、MediaStore、AppWidget、WorkManager"]
+    end
+
+    subgraph Tests["驗證"]
+        UnitTests["src/test\nRepository、ViewModel、Analytics、Reminder、Boundary tests"]
+        UiTests["src/androidTest\nCompose UI test"]
+        DebugOnly["src/debug\nGradeReminderDebugReceiver"]
+    end
+
+    Android --> Main
+    Main --> AppShell
+    Main --> LockUi
+    AppShell --> UI
+    UI --> ViewModels
+    Login --> ScoreVm
+    ScoreVm --> GradeRepo
+    ScoreVm --> Analysis
+    ScoreVm --> Exporter
+    ScoreVm --> Reminder
+    ScheduleVm --> ScheduleRepo
+    SettingsVm --> Stores
+    SettingsVm --> Fcm
+    SettingsVm --> GitHub
+    GradeRepo --> SchoolClient
+    GradeRepo --> Stores
+    ScheduleRepo --> SchoolClient
+    ScheduleRepo --> Stores
+    SchoolClient --> CookieJar
+    SchoolClient --> School
+    Reminder --> GradeRepo
+    Reminder --> Stores
+    Widget --> Stores
+    Fcm --> Firebase
+    Logger --> Firebase
+    Sanitizer --> Logger
+    FileProvider --> AndroidSystem
+    Biometric --> AndroidSystem
+    Stores --> AndroidSystem
+    Reminder --> AndroidSystem
+    Widget --> AndroidSystem
+    Channels --> AndroidSystem
+    Workflows --> GitHub
+    Workflows --> Android
+    Demo --> Workflows
+    UnitTests --> ScoreVm
+    UnitTests --> GradeRepo
+    UiTests --> AppShell
+    DebugOnly --> Reminder
 ```
 
+核心資料流是 `Compose UI -> ViewModel -> Repository -> SchoolGradeClient -> 學校系統`。Repository 會先讀取本機快取與 session，必要時才透過 `SchoolGradeClient` 連線；背景提醒、桌面 Widget、通知、更新檢查與匯出則透過各自的 Android 系統服務保持在 app 邊界內。
+
 ## 專案結構
 
 | 目錄 | 說明 | 文件 |