feat(ui): 主题切换 + 语言持久化 + About 对话框

- 新增 light/dark 主题调色板与 Windows 注册表系统主题探测
- 偏好设置对话框：主题三选一 + 语言下拉(en/zh-CN/de)，即时生效
- 持久化 Language/Theme/AutoLockMinutes/MinimizeToTray 至 YAML 顶层
- 启动时按 config 中保存的语言初始化 i18n
- About 对话框展示 version/runtime/项目地址/许可证
- 全部硬编码颜色迁移到 themePalette，为深色模式做准备

cmd/winauth/main.go

@@ -6,10 +6,12 @@ import (
 
 	"github.com/spf13/cobra"
 
+	"git.wxccs.org/iceking2nd/winauth-go/internal/config"
 	"git.wxccs.org/iceking2nd/winauth-go/internal/global"
 	"git.wxccs.org/iceking2nd/winauth-go/internal/i18n"
 	"git.wxccs.org/iceking2nd/winauth-go/internal/logging"
 	"git.wxccs.org/iceking2nd/winauth-go/internal/ui"
+	"git.wxccs.org/iceking2nd/winauth-go/internal/version"
 	"git.wxccs.org/iceking2nd/winauth-go/internal/win32"
 )
 
@@ -53,7 +55,8 @@ func main() {
 			}
 
 			const fn = "cmd.winauth.main"
-			global.Log.WithField("func", fn).Info("winauth-go starting")
+			global.Log.WithField("func", fn).
+				WithField("version", version.String()).Info("winauth-go starting")
 
 			release, alreadyRunning, err := win32.AcquireInstanceLock(singleInstanceMutex)
 			if err != nil {
@@ -70,7 +73,12 @@ func main() {
 				defer release()
 			}
 
-			if err := i18n.Init(""); err != nil {
+			// Peek the config (without password) to recover the user's
+			// last language choice before initialising i18n. Encrypted
+			// configs still expose Language at the YAML top level so we
+			// can localise the password prompt itself.
+			lang := preferredLanguage(configPath)
+			if err := i18n.Init(lang); err != nil {
 				global.Log.WithField("func", fn).WithError(err).Warn("i18n init failed; falling back to keys")
 			}
 
@@ -91,3 +99,19 @@ func main() {
 		os.Exit(1)
 	}
 }
+
+// preferredLanguage reads the user's saved language tag out of the YAML
+// config without requiring a passphrase. We resolve the default config
+// path when configPath is blank and silently return "" on any failure;
+// callers fall back to the i18n default in that case. Encrypted configs
+// still expose the top-level Language field so this works for them too.
+func preferredLanguage(configPath string) string {
+	if configPath == "" {
+		configPath = config.DefaultPath()
+	}
+	cfg, _ := config.LoadYAML(configPath, nil)
+	if cfg == nil {
+		return ""
+	}
+	return cfg.Language
+}