feat: add app update checks and standalone release publishing panel

mobile/android/app/src/main/kotlin/com/tpschedule/app/MainActivity.kt

@@ -9,6 +9,7 @@ class MainActivity : FlutterActivity() {
     private var calendar: CalendarBridge? = null
     private var reminders: ReminderSystemBridge? = null
     private var schoolDocuments: SchoolDocumentBridge? = null
+    private var updateBrowser: UpdateBrowserBridge? = null
     override fun onCreate(savedInstanceState: Bundle?) {
         super.onCreate(savedInstanceState)
         if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.S) {
@@ -23,10 +24,14 @@ class MainActivity : FlutterActivity() {
         reminders = ReminderSystemBridge(this, flutterEngine.dartExecutor.binaryMessenger)
         schoolDocuments?.close()
         schoolDocuments = SchoolDocumentBridge(flutterEngine)
+        updateBrowser?.close()
+        updateBrowser = UpdateBrowserBridge(this, flutterEngine.dartExecutor.binaryMessenger)
     }
     override fun cleanUpFlutterEngine(flutterEngine: FlutterEngine) {
         schoolDocuments?.close()
         schoolDocuments = null
+        updateBrowser?.close()
+        updateBrowser = null
         super.cleanUpFlutterEngine(flutterEngine)
     }
     override fun onRequestPermissionsResult(requestCode: Int, permissions: Array<out String>, grantResults: IntArray) {
@@ -37,6 +42,7 @@ class MainActivity : FlutterActivity() {
         calendar?.close()
         reminders?.close()
         schoolDocuments?.close()
+        updateBrowser?.close()
         super.onDestroy()
     }
 }

mobile/android/app/src/main/kotlin/com/tpschedule/app/UpdateBrowserBridge.kt

@@ -0,0 +1,33 @@
+package com.tpschedule.app
+
+import android.app.Activity
+import android.content.ActivityNotFoundException
+import android.content.Intent
+import android.net.Uri
+import io.flutter.plugin.common.BinaryMessenger
+import io.flutter.plugin.common.MethodChannel
+
+class UpdateBrowserBridge(private val activity: Activity, messenger: BinaryMessenger) {
+    private val channel = MethodChannel(messenger, "com.tpschedule.app/updates")
+    init {
+        channel.setMethodCallHandler { call, result ->
+            if (call.method != "openDownload") {
+                result.notImplemented()
+            } else {
+                val value = call.argument<String>("url")
+                val uri = value?.let { Uri.parse(it) }
+                if (value == null || value.length > 2048 || value.any { it.isWhitespace() || it.code < 32 } ||
+                    uri?.scheme != "https" || uri.host.isNullOrBlank() || !uri.userInfo.isNullOrEmpty()) {
+                    result.success(false)
+                } else {
+                    try {
+                        activity.startActivity(Intent(Intent.ACTION_VIEW, uri).addCategory(Intent.CATEGORY_BROWSABLE))
+                        result.success(true)
+                    } catch (_: ActivityNotFoundException) { result.success(false) }
+                      catch (_: SecurityException) { result.success(false) }
+                }
+            }
+        }
+    }
+    fun close() { channel.setMethodCallHandler(null) }
+}