新增: 自动升级体系 + WorkerW重建检测 + 知识卡片优化

自动升级:
- 版本变量注入 (-ldflags -X main.version)
- 远程 version.json 检查 + 弹窗提示(非强制右下角/强制居中)
- updater.exe 嵌入主程序, 运行时释放到临时目录
- 下载+SHA256校验+备份+替换+回滚 全流程
- 托盘菜单"检查更新"

稳定性:
- WorkerW 重建自动检测(每10s)并重新嵌入
- 左键托盘点击防抖
- 设置窗口已打开时正确前置

优化:
- 知识卡片prompt改为面向开发者的硬核内容
- 配置目录统一到 ~/.u-desktop/
- 设置窗口WebView2数据目录改为configDir下

settings.go

@@ -104,10 +104,12 @@ func refreshVisibleCards(cfg, oldCfg *Config) {
 
 func openSettingsWindow() {
 	settingsMu.Lock()
-	if settingsOpen && settingsHwnd != 0 {
+	if settingsOpen {
 		settingsMu.Unlock()
-		procShowWindow.Call(settingsHwnd, 9)
-		procGetForegroundWindow.Call(settingsHwnd)
+		if settingsHwnd != 0 {
+			procShowWindow.Call(settingsHwnd, 9)
+			procGetForegroundWindow.Call(settingsHwnd)
+		}
 		return
 	}
 	settingsOpen = true
@@ -123,7 +125,7 @@ func openSettingsWindow() {
 			runtime.UnlockOSThread()
 		}()
 
-		dataDir := filepath.Join(os.TempDir(), "u-desktop-settings")
+		dataDir := filepath.Join(configDir(), "settings-data")
 		os.MkdirAll(dataDir, 0755)
 
 		w := webview2.NewWithOptions(webview2.WebViewOptions{
@@ -194,7 +196,7 @@ func openSettingsWindow() {
 				"photoDir":         cfg.PhotoDir,
 				"photoInterval":    cfg.PhotoInterval,
 				"photoCard":        !cfg.HidePhoto,
-				"photoFrameMode":  cfg.PhotoFrameMode,
+				"photoFrameMode":   cfg.PhotoFrameMode,
 				"autoStart":        isAutoStartEnabled(),
 			})
 			return string(data)
@@ -252,13 +254,13 @@ func openSettingsWindow() {
 					for _, card := range []string{"time", "weather", "zodiac", "ainews", "knowledge"} {
 						evalJS(fmt.Sprintf("if(window.setCardVisible) setCardVisible('%s',false)", card))
 					}
+				} else {
+					reloadWallpaper()
 				}
 			}
 			if v, ok := data["photoCard"]; ok {
 				cfg.HidePhoto = !v
-				saveConfig(cfg)
 				evalJS(fmt.Sprintf("if(window.setCardVisible) setCardVisible('photo',%v)", v))
-				refreshVisibleCards(cfg, &oldCfg)
 				if cfg.PhotoDir != "" {
 					if v {
 						restartPhotoLoop()
@@ -266,10 +268,9 @@ func openSettingsWindow() {
 						stopPhotoLoop()
 					}
 				}
-			} else {
-				saveConfig(cfg)
-				refreshVisibleCards(cfg, &oldCfg)
 			}
+			saveConfig(cfg)
+			refreshVisibleCards(cfg, &oldCfg)
 			return ""
 		})
 
@@ -383,15 +384,15 @@ func openSettingsWindow() {
 
 		w.Bind("pickGradientColor", func() string {
 			hwnd := uintptr(w.Window())
-			c1 := colorPickerDialog(hwnd, "")
+			cfg := loadConfig()
+			c1 := colorPickerDialog(hwnd, cfg.Color1)
 			if c1 == "" {
 				return ""
 			}
-			c2 := colorPickerDialog(hwnd, "")
+			c2 := colorPickerDialog(hwnd, cfg.Color2)
 			if c2 == "" {
 				c2 = "#16213e"
 			}
-			cfg := loadConfig()
 			cfg.WallpaperType = WPColor
 			cfg.Color1 = c1
 			cfg.Color2 = c2
@@ -494,9 +495,10 @@ func openSettingsWindow() {
 		w.SetHtml(settingsHTML)
 
 		hwnd := uintptr(w.Window())
-		// disable resize
-		style, _, _ := procGetWindowLongPtrW.Call(hwnd, gwlStyle)
-		procSetWindowLongPtrW.Call(hwnd, gwlStyle, style & ^uintptr(wsSizebox|wsMaxbox))
+		// disable resize + hide from taskbar
+			style, _, _ := procGetWindowLongPtrW.Call(hwnd, gwlStyle)
+			procSetWindowLongPtrW.Call(hwnd, gwlStyle, style & ^uintptr(wsSizebox|wsMaxbox))
+			procSetWindowLongPtrW.Call(hwnd, gwlExStyle, wsExToolwindow)
 
 		// resizeToFit: JS measures content, Go adjusts window frame
 		w.Bind("resizeToFit", func(contentW, contentH int) string {