fix: 数据持久化到/app/data目录，简化部署配置

- 配置文件和SQLite数据库存储在/app/data
- Docker volume持久化数据
- 无需预设环境变量，安装向导自动配置

backend/internal/database/database.go

@@ -11,7 +11,6 @@ import (
 	"context"
 	"fmt"
 	"log"
-	"os"
 	"path/filepath"
 	"time"
 	"verification-platform-backend/internal/config"
@@ -52,26 +51,18 @@ func initDatabase() {
 }
 
 func initSQLite() {
-	dbPath := "verification_platform.db"
-	absPath, err := filepath.Abs(dbPath)
-	if err != nil {
-		log.Fatal("Failed to get absolute path:", err.Error())
-	}
-
-	wd, err := os.Getwd()
-	if err == nil && filepath.Base(wd) == "cmd" {
-		absPath = filepath.Join(filepath.Dir(wd), "verification_platform.db")
-	}
+	dataDir := config.GetDataDir()
+	dbPath := filepath.Join(dataDir, "verification_platform.db")
 
 	var errOpen error
-	DB, errOpen = gorm.Open(sqlite.Open(absPath), &gorm.Config{
+	DB, errOpen = gorm.Open(sqlite.Open(dbPath), &gorm.Config{
 		Logger:                                   logger.Default.LogMode(logger.Silent),
 		DisableForeignKeyConstraintWhenMigrating: true,
 	})
 	if errOpen != nil {
 		log.Fatal("Failed to create SQLite database:", errOpen.Error())
 	}
-	log.Printf("Using SQLite database: %s\n", absPath)
+	log.Printf("Using SQLite database: %s\n", dbPath)
 
 	if sqlDB, err := DB.DB(); err == nil {
 		sqlDB.SetMaxIdleConns(10)
@@ -132,27 +123,19 @@ func initAutoDetect() {
 	})
 
 	if err != nil {
-		log.Println("Failed to connect to MySQL, using SQLite database for development:", err.Error())
+		log.Println("Failed to connect to MySQL, using SQLite database:", err.Error())
 
-		dbPath := "verification_platform.db"
-		absPath, err := filepath.Abs(dbPath)
-		if err != nil {
-			log.Fatal("Failed to get absolute path:", err.Error())
-		}
+		dataDir := config.GetDataDir()
+		dbPath := filepath.Join(dataDir, "verification_platform.db")
 
-		wd, err := os.Getwd()
-		if err == nil && filepath.Base(wd) == "cmd" {
-			absPath = filepath.Join(filepath.Dir(wd), "verification_platform.db")
-		}
-
-		DB, err = gorm.Open(sqlite.Open(absPath), &gorm.Config{
+		DB, err = gorm.Open(sqlite.Open(dbPath), &gorm.Config{
 			Logger:                                   logger.Default.LogMode(logger.Silent),
 			DisableForeignKeyConstraintWhenMigrating: true,
 		})
 		if err != nil {
 			log.Fatal("Failed to create SQLite database:", err.Error())
 		}
-		log.Printf("Database file path: %s\n", absPath)
+		log.Printf("Using SQLite database: %s\n", dbPath)
 	}
 
 	if sqlDB, err := DB.DB(); err == nil {