feat:基础功能实现

feat: 重构 TodoList 架构，新增动态 API 与 MAUI 内嵌 Web 服务
feat:优化交互逻辑,优化发布流程

TodoList/Services/FileDataService.cs

@@ -1,6 +1,7 @@
 using System;
 using System.Collections.Generic;
 using System.IO;
+using System.Linq;
 using System.Text.Json;
 using System.Threading.Tasks;
 using TodoList.Models;
@@ -19,7 +20,7 @@ namespace TodoList.Services
             _filePath = Path.Combine(folder, "tasks.json");
         }
 
-        public async Task<List<TodoItem>> LoadTasksAsync()
+        public async Task<List<TodoItem>> LoadTasksAsync(bool? completed = null)
         {
             if (!File.Exists(_filePath))
             {
@@ -30,7 +31,13 @@ namespace TodoList.Services
             {
                 using var stream = File.OpenRead(_filePath);
                 var items = await JsonSerializer.DeserializeAsync<List<TodoItem>>(stream);
-                return items ?? new List<TodoItem>();
+                var tasks = items ?? new List<TodoItem>();
+                
+                if (completed.HasValue)
+                {
+                    return tasks.Where(t => t.IsCompleted == completed.Value).ToList();
+                }
+                return tasks;
             }
             catch
             {
@@ -38,7 +45,7 @@ namespace TodoList.Services
             }
         }
 
-        public async Task SaveTaskAsync(TodoItem task)
+        public async Task<TodoItem> SaveTaskAsync(TodoItem task)
         {
             var tasks = await LoadTasksAsync();
             var existing = tasks.Find(t => t.Id == task.Id);
@@ -48,6 +55,34 @@ namespace TodoList.Services
             }
             tasks.Add(task);
             await SaveAllAsync(tasks);
+            return task;
+        }
+
+        public async Task<TodoItem> UpdateTaskAsync(TodoItem task)
+        {
+            var tasks = await LoadTasksAsync();
+            var existing = tasks.Find(t => t.Id == task.Id);
+            if (existing != null)
+            {
+                tasks.Remove(existing);
+                tasks.Add(task);
+                await SaveAllAsync(tasks);
+            }
+            return task;
+        }
+
+        public async Task<TodoItem> ToggleCompleteAsync(string id)
+        {
+            var tasks = await LoadTasksAsync();
+            var task = tasks.Find(t => t.Id == id);
+            if (task != null)
+            {
+                task.IsCompleted = !task.IsCompleted;
+                task.CompletedAt = task.IsCompleted ? DateTime.Now : null;
+                task.SyncStatus = SyncStatus.Pending;
+                await SaveAllAsync(tasks);
+            }
+            return task;
         }
 
         public async Task SaveAllAsync(List<TodoItem> tasks)