feat: admin app version mgmt + notification system

- New tables: app_config, notifications
- Admin views: App Version editor, Notification sender
- API: GET /api/notifications, POST /api/notifications/:id/read, POST /api/notifications/read-all
- App version now stored in DB, editable by super admin
- Notifications: send to all users or specific user
- Android notification models + API client
- Sidebar: App Version + Notifications links for super_admin

android/app/src/main/java/com/devlab/app/data/api/ApiService.kt

@@ -49,4 +49,16 @@ interface ApiService {
 
     @GET("api/app-version")
     suspend fun checkVersion(): ApiResponse<AppVersionResponse>
+
+    @GET("api/notifications")
+    suspend fun getNotifications(
+        @Query("page") page: Int = 1,
+        @Query("per_page") perPage: Int = 20
+    ): NotificationListResponse
+
+    @POST("api/notifications/{id}/read")
+    suspend fun markNotificationRead(@Path("id") id: Int): ApiResponse<Map<String, Boolean>>
+
+    @POST("api/notifications/read-all")
+    suspend fun markAllNotificationsRead(): ApiResponse<Map<String, Boolean>>
 }

android/app/src/main/java/com/devlab/app/data/model/ApiResponse.kt

@@ -25,3 +25,12 @@ data class AppVersionResponse(
     val force_update: Boolean = false,
     val release_notes: String = ""
 )
+
+@Serializable
+data class NotificationListResponse(
+    val success: Boolean = true,
+    val data: List<AppNotification> = emptyList(),
+    val error: String? = null,
+    val pagination: Pagination? = null,
+    val unread_count: Int = 0
+)

android/app/src/main/java/com/devlab/app/data/model/Notification.kt

@@ -0,0 +1,11 @@
+package com.devlab.app.data.model
+
+@kotlinx.serialization.Serializable
+data class AppNotification(
+    val id: Int = 0,
+    val title: String = "",
+    val message: String = "",
+    val type: String = "info",
+    val is_read: Int = 0,
+    val created_at: String = "",
+)