feat: implement core app screens, viewmodels, and repository layer for link management and navigation

app/src/main/java/com/shaarit/presentation/nav/NavGraph.kt

@@ -49,6 +49,9 @@ sealed class Screen(val route: String) {
     }
     object Reminders : Screen("reminders")
     object Todo : Screen("todo")
+    object TodoDetail : Screen("todoDetail/{linkId}") {
+        fun createRoute(linkId: Int): String = "todoDetail/$linkId"
+    }
 }
 
 @Composable
@@ -163,6 +166,7 @@ fun AppNavGraph(
                 },
                 onNavigateToReminders = { navController.navigate(Screen.Reminders.route) },
                 onNavigateToTodo = { navController.navigate(Screen.Todo.route) },
+                onNavigateToTodoDetail = { linkId -> navController.navigate(Screen.TodoDetail.createRoute(linkId)) },
                 onPlayAudio = onPlayAudio,
                 initialTagFilter = tag,
                 initialCollectionId = collectionId
@@ -355,5 +359,20 @@ fun AppNavGraph(
                 onNavigateBack = { navController.popBackStack() }
             )
         }
+
+        composable(
+            route = Screen.TodoDetail.route,
+            arguments = listOf(
+                navArgument("linkId") {
+                    type = NavType.IntType
+                }
+            )
+        ) { backStackEntry ->
+            val linkId = backStackEntry.arguments?.getInt("linkId") ?: 0
+            com.shaarit.presentation.todo.TodoDetailScreen(
+                linkId = linkId,
+                onNavigateBack = { navController.popBackStack() }
+            )
+        }
     }
 }