Phase 4: 全局快捷键拦截 (Win32 API)

- 新增 HotKeyManager (Helpers/), 使用 user32.dll RegisterHotKey/UnregisterHotKey 注册系统级快捷键

- 支持 Ctrl/Alt/Shift/Win 修饰键组合, 单字符键和命名键(F1-F12等)解析

- MainWindow.OnSourceInitialized 挂载 HwndSource.AddHook 拦截 WM_HOTKEY 消息

- 启动时自动注册所有含快捷键的工具, 工具增删改后自动重新注册

- 快捷键冲突时记录 Win32 错误码, 无效格式打印警告

- 新增 12 个 HotKeyManager 单元测试 (73 tests total)

PersonalToolBox.Tests/Helpers/HotKeyManagerTests.cs

@@ -0,0 +1,135 @@
+using Moq;
+using PersonalToolBox.Helpers;
+using PersonalToolBox.Models;
+using PersonalToolBox.Services;
+
+namespace PersonalToolBox.Tests.Helpers;
+
+public class HotKeyManagerTests
+{
+    [Fact]
+    public void TryParseHotKey_ValidCtrlAltT_ReturnsCorrectModifiersAndVk()
+    {
+        var result = HotKeyManager.TryParseHotKey("Ctrl+Alt+T", out uint mod, out uint vk);
+
+        Assert.True(result);
+        Assert.NotEqual(0u, mod);
+        // 'T' → VK = 0x54
+        Assert.Equal((uint)'T', vk);
+    }
+
+    [Fact]
+    public void TryParseHotKey_ValidCtrlShiftF1_ReturnsCorrectVk()
+    {
+        var result = HotKeyManager.TryParseHotKey("Ctrl+Shift+F1", out uint mod, out uint vk);
+
+        Assert.True(result);
+        Assert.NotEqual(0u, mod);
+        // F1 → VK_F1 = 0x70
+        Assert.Equal(0x70u, vk);
+    }
+
+    [Fact]
+    public void TryParseHotKey_OnlyModifier_ReturnsFalse()
+    {
+        var result = HotKeyManager.TryParseHotKey("Ctrl", out _, out _);
+
+        Assert.False(result);
+    }
+
+    [Fact]
+    public void TryParseHotKey_OnlyKey_ReturnsFalse()
+    {
+        var result = HotKeyManager.TryParseHotKey("T", out _, out _);
+
+        Assert.False(result);
+    }
+
+    [Fact]
+    public void TryParseHotKey_Empty_ReturnsFalse()
+    {
+        var result = HotKeyManager.TryParseHotKey("", out _, out _);
+        Assert.False(result);
+    }
+
+    [Fact]
+    public void TryParseHotKey_Null_ReturnsFalse()
+    {
+        var result = HotKeyManager.TryParseHotKey(null!, out _, out _);
+        Assert.False(result);
+    }
+
+    [Fact]
+    public void TryParseHotKey_Whitespace_ReturnsFalse()
+    {
+        var result = HotKeyManager.TryParseHotKey("   ", out _, out _);
+        Assert.False(result);
+    }
+
+    [Fact]
+    public void TryParseHotKey_WinKey_B_ReturnsCorrectVk()
+    {
+        var result = HotKeyManager.TryParseHotKey("Win+B", out uint mod, out uint vk);
+
+        Assert.True(result);
+        Assert.Equal((uint)'B', vk);
+    }
+
+    [Fact]
+    public void TryParseHotKey_UnknownModifier_ReturnsFalse()
+    {
+        var result = HotKeyManager.TryParseHotKey("Foo+T", out _, out _);
+
+        Assert.False(result);
+    }
+
+    [Fact]
+    public void RegisterAll_SkipsEmptyHotKeys()
+    {
+        var logMock = new Mock<ILogService>();
+        var processMock = new Mock<IProcessExecutionService>();
+        var manager = new HotKeyManager(logMock.Object, processMock.Object);
+
+        var tools = new[]
+        {
+            new ToolItem { Name = "NoHotkey", HotKey = "" },
+            new ToolItem { Name = "BlankHotkey", HotKey = "   " }
+        };
+
+        // Should not throw
+        manager.RegisterAll(tools);
+    }
+
+    [Fact]
+    public void RegisterAll_InvalidFormat_LogsWarning()
+    {
+        var logMock = new Mock<ILogService>();
+        var processMock = new Mock<IProcessExecutionService>();
+        var manager = new HotKeyManager(logMock.Object, processMock.Object);
+
+        // Initialize needs a hwnd, but RegisterAll calls Register which checks _hwnd
+        // So calling RegisterAll without Initialize should be a no-op
+        var tools = new[]
+        {
+            new ToolItem { Name = "Bad", HotKey = "not-a-valid-key" }
+        };
+
+        // hwnd is IntPtr.Zero, so should skip silently
+        manager.RegisterAll(tools);
+
+        // hwnd is zero, so Register is skipped entirely
+        logMock.Verify(x => x.Warning(It.IsAny<string>()), Times.Never);
+    }
+
+    [Fact]
+    public void TryHandleMessage_NonWMHOTKEY_ReturnsFalse()
+    {
+        var logMock = new Mock<ILogService>();
+        var processMock = new Mock<IProcessExecutionService>();
+        var manager = new HotKeyManager(logMock.Object, processMock.Object);
+
+        var handled = manager.TryHandleMessage(9999, IntPtr.Zero, IntPtr.Zero);
+
+        Assert.False(handled);
+    }
+}