fix: resolve Windows path mismatch between setup write and runtime read

backend/internal/config/config.go

@@ -8,6 +8,8 @@ import (
 	"log/slog"
 	"net/url"
 	"os"
+	"path/filepath"
+	"runtime"
 	"strings"
 	"time"
 
@@ -944,6 +946,30 @@ func Load() (*Config, error) {
 	return load(false)
 }
 
+// getDataDir returns the data directory used by setup, mirroring setup.GetDataDir().
+// This keeps config search paths consistent with where setup writes files,
+// preventing path drift on Windows where /app/data maps to the drive root.
+func getDataDir() string {
+	if dir := os.Getenv("DATA_DIR"); dir != "" {
+		return dir
+	}
+	if runtime.GOOS == "linux" {
+		dockerDataDir := "/app/data"
+		if info, err := os.Stat(dockerDataDir); err == nil && info.IsDir() {
+			testFile := dockerDataDir + "/.write_test"
+			if f, err := os.Create(testFile); err == nil {
+				_ = f.Close()
+				_ = os.Remove(testFile)
+				return dockerDataDir
+			}
+		}
+	}
+	if exePath, err := os.Executable(); err == nil {
+		return filepath.Dir(exePath)
+	}
+	return "."
+}
+
 // LoadForBootstrap 读取启动阶段配置。
 //
 // 启动阶段允许 jwt.secret 先留空，后续由数据库初始化流程补齐并再次完整校验。
@@ -955,18 +981,12 @@ func load(allowMissingJWTSecret bool) (*Config, error) {
 	viper.SetConfigName("config")
 	viper.SetConfigType("yaml")
 
-	// Add config paths in priority order
-	// 1. DATA_DIR environment variable (highest priority)
-	if dataDir := os.Getenv("DATA_DIR"); dataDir != "" {
-		viper.AddConfigPath(dataDir)
-	}
-	// 2. Docker data directory
-	viper.AddConfigPath("/app/data")
-	// 3. Current directory
-	viper.AddConfigPath(".")
-	// 4. Config subdirectory
+	// Add config paths in the same priority order used by setup.GetDataDir(),
+	// so runtime and setup always agree on where the config file lives.
+	viper.AddConfigPath(getDataDir())
+	// Fallback: Config subdirectory (legacy layout)
 	viper.AddConfigPath("./config")
-	// 5. System config directory
+	// Fallback: System config directory (Linux package installations)
 	viper.AddConfigPath("/etc/sub2api")
 
 	// 环境变量支持

backend/internal/pkg/sysutil/restart.go

@@ -22,7 +22,7 @@ import (
 //   - Service configured with Restart=always in systemd unit file
 func RestartService() error {
 	if runtime.GOOS != "linux" {
-		log.Println("Service restart via exit only works on Linux with systemd")
+		log.Println("Automatic restart is not supported on this platform. Please restart the application manually.")
 		return nil
 	}
 

backend/internal/pkg/timezone/timezone.go

@@ -21,7 +21,7 @@ var (
 // Example timezone values: "Asia/Shanghai", "America/New_York", "UTC"
 func Init(tz string) error {
 	if tz == "" {
-		tz = "Asia/Shanghai" // Default timezone
+		tz = "UTC" // Default to UTC for cross-platform compatibility
 	}
 
 	loc, err := time.LoadLocation(tz)

backend/internal/setup/handler.go

@@ -5,6 +5,7 @@ import (
 	"net/http"
 	"net/mail"
 	"regexp"
+	"runtime"
 	"strings"
 	"sync"
 	"time"
@@ -348,8 +349,12 @@ func install(c *gin.Context) {
 		sysutil.RestartServiceAsync()
 	}()
 
+	restartMsg := "Installation completed successfully. Service will restart automatically."
+	if runtime.GOOS != "linux" {
+		restartMsg = "Installation completed successfully. Please restart the application manually."
+	}
 	response.Success(c, gin.H{
-		"message": "Installation completed successfully. Service will restart automatically.",
-		"restart": true,
+		"message": restartMsg,
+		"restart": runtime.GOOS == "linux",
 	})
 }

backend/internal/setup/setup.go

@@ -8,6 +8,8 @@ import (
 	"encoding/hex"
 	"fmt"
 	"os"
+	"path/filepath"
+	"runtime"
 	"strconv"
 	"strings"
 	"time"
@@ -38,26 +40,37 @@ func setupDefaultAdminConcurrency() int {
 }
 
 // GetDataDir returns the data directory for storing config and lock files.
-// Priority: DATA_DIR env > /app/data (if exists and writable) > current directory
+// Priority: DATA_DIR env > /app/data (Linux/Docker only, if exists and writable) > executable directory > current directory
 func GetDataDir() string {
 	// Check DATA_DIR environment variable first
 	if dir := os.Getenv("DATA_DIR"); dir != "" {
 		return dir
 	}
 
-	// Check if /app/data exists and is writable (Docker environment)
-	dockerDataDir := "/app/data"
-	if info, err := os.Stat(dockerDataDir); err == nil && info.IsDir() {
-		// Try to check if writable by creating a temp file
-		testFile := dockerDataDir + "/.write_test"
-		if f, err := os.Create(testFile); err == nil {
-			_ = f.Close()
-			_ = os.Remove(testFile)
-			return dockerDataDir
+	// Check if /app/data exists and is writable — Docker/Linux environments only.
+	// Skipped on Windows because the path /app/data resolves to the current drive root
+	// (e.g., C:\app\data), causing a mismatch between setup write path and runtime read path.
+	if runtime.GOOS == "linux" {
+		dockerDataDir := "/app/data"
+		if info, err := os.Stat(dockerDataDir); err == nil && info.IsDir() {
+			// Try to check if writable by creating a temp file
+			testFile := dockerDataDir + "/.write_test"
+			if f, err := os.Create(testFile); err == nil {
+				_ = f.Close()
+				_ = os.Remove(testFile)
+				return dockerDataDir
+			}
 		}
 	}
 
-	// Default to current directory
+	// Use the executable's directory so setup and runtime always agree on the path,
+	// even when the current working directory differs (common on Windows when launching
+	// via double-click or as a service).
+	if exePath, err := os.Executable(); err == nil {
+		return filepath.Dir(exePath)
+	}
+
+	// Final fallback: current directory
 	return "."
 }
 
@@ -432,7 +445,7 @@ func writeConfigFile(cfg *SetupConfig) error {
 	// Ensure timezone has a default value
 	tz := cfg.Timezone
 	if tz == "" {
-		tz = "Asia/Shanghai"
+		tz = "UTC"
 	}
 
 	// Prepare config for YAML (exclude sensitive data and admin config)