实现 MinIO 对象存储图片流水线（可迁移 OSS）

- 新增 S3 兼容 Storage 抽象与 MinIO 实现，compose 启动 MinIO
- 上传接口：校验 → 缩放 → WebP → 主图/缩略图入库
- 消息图片 content 改为对象 URL，拒绝 base64
- 工作台/访客端改为先上传再发消息

server/internal/config/config.go

@@ -2,6 +2,7 @@ package config
 
 import (
 	"os"
+	"strconv"
 	"time"
 )
 
@@ -9,6 +10,7 @@ type Config struct {
 	Server   ServerConfig
 	Database DatabaseConfig
 	JWT      JWTConfig
+	Storage  StorageConfig
 }
 
 type ServerConfig struct {
@@ -30,6 +32,20 @@ type JWTConfig struct {
 	ExpireTime time.Duration
 }
 
+// StorageConfig S3 兼容对象存储（MinIO / OSS / COS / S3 共用字段）
+type StorageConfig struct {
+	Endpoint     string // 如 localhost:9000 或 oss-cn-hangzhou.aliyuncs.com
+	AccessKey    string
+	SecretKey    string
+	Bucket       string
+	UseSSL       bool
+	Region       string
+	PublicBase   string // 浏览器可访问前缀，如 http://localhost:9000/kefu
+	MaxUploadMB  int
+	MaxImageEdge int // 最长边像素
+	WebPQuality  float32
+}
+
 func Load() *Config {
 	return &Config{
 		Server: ServerConfig{
@@ -38,7 +54,7 @@ func Load() *Config {
 		},
 		Database: DatabaseConfig{
 			Host:     getEnv("DB_HOST", "localhost"),
-			Port:     getEnv("DB_PORT", "5432"),
+			Port:     getEnv("DB_PORT", "5433"),
 			User:     getEnv("DB_USER", "postgres"),
 			Password: getEnv("DB_PASSWORD", "postgres"),
 			Name:     getEnv("DB_NAME", "kefu_sys"),
@@ -48,6 +64,18 @@ func Load() *Config {
 			Secret:     getEnv("JWT_SECRET", "kefu-sys-secret-key"),
 			ExpireTime: 24 * time.Hour,
 		},
+		Storage: StorageConfig{
+			Endpoint:     getEnv("STORAGE_ENDPOINT", "localhost:9000"),
+			AccessKey:    getEnv("STORAGE_ACCESS_KEY", "minioadmin"),
+			SecretKey:    getEnv("STORAGE_SECRET_KEY", "minioadmin"),
+			Bucket:       getEnv("STORAGE_BUCKET", "kefu"),
+			UseSSL:       getEnvBool("STORAGE_USE_SSL", false),
+			Region:       getEnv("STORAGE_REGION", "us-east-1"),
+			PublicBase:   getEnv("STORAGE_PUBLIC_BASE_URL", "http://localhost:9000/kefu"),
+			MaxUploadMB:  getEnvInt("STORAGE_MAX_UPLOAD_MB", 10),
+			MaxImageEdge: getEnvInt("STORAGE_MAX_IMAGE_EDGE", 1920),
+			WebPQuality:  float32(getEnvInt("STORAGE_WEBP_QUALITY", 80)),
+		},
 	}
 }
 
@@ -62,3 +90,27 @@ func getEnv(key, fallback string) string {
 	}
 	return fallback
 }
+
+func getEnvBool(key string, fallback bool) bool {
+	v := os.Getenv(key)
+	if v == "" {
+		return fallback
+	}
+	b, err := strconv.ParseBool(v)
+	if err != nil {
+		return fallback
+	}
+	return b
+}
+
+func getEnvInt(key string, fallback int) int {
+	v := os.Getenv(key)
+	if v == "" {
+		return fallback
+	}
+	n, err := strconv.Atoi(v)
+	if err != nil {
+		return fallback
+	}
+	return n
+}