feat(deploy): 在线更新 - 新增后台检查、强制备份迁移与失败自动回退

backend/cmd/migrate-schema/main.go

@@ -0,0 +1,64 @@
+package main
+
+import (
+	"encoding/json"
+	"fmt"
+	"log"
+	"os"
+	"strings"
+
+	"infinite-canvas/backend/internal/database"
+)
+
+func main() {
+	command := "up"
+	if len(os.Args) > 1 {
+		command = strings.ToLower(strings.TrimSpace(os.Args[1]))
+	}
+	db, err := database.Open(database.Config{
+		Driver:  env("CANVAS_DATABASE_DRIVER", "sqlite"),
+		DSN:     os.Getenv("DATABASE_URL"),
+		DataDir: env("CANVAS_BACKEND_DATA_DIR", "data"),
+	})
+	if err != nil {
+		log.Fatal(err)
+	}
+	if err := database.ConfigurePool(db); err != nil {
+		log.Fatal(err)
+	}
+	sqlDB, err := db.DB()
+	if err != nil {
+		log.Fatal(err)
+	}
+	defer sqlDB.Close()
+
+	switch command {
+	case "up":
+		if err := database.MigrateSchema(db); err != nil {
+			log.Fatal(err)
+		}
+	case "status":
+	case "verify":
+		if err := database.RequireSchemaVersion(db); err != nil {
+			log.Fatal(err)
+		}
+	default:
+		log.Fatalf("未知命令 %q；可用命令：up、status、verify", command)
+	}
+	status, err := database.ReadSchemaStatus(db)
+	if err != nil {
+		log.Fatal(err)
+	}
+	encoded, err := json.Marshal(status)
+	if err != nil {
+		log.Fatal(err)
+	}
+	fmt.Println(string(encoded))
+}
+
+func env(key string, fallback string) string {
+	if value := strings.TrimSpace(os.Getenv(key)); value != "" {
+		return value
+	}
+	return fallback
+}