feat: 并发分组系统 + 品牌/Logo 上传 + 兑换码开关 + 文档分辨率表

并发分组(新功能):
- 新表 concurrency_groups(名称/上限/默认),用户加 concurrency_group_id
- 启动自动建「默认并发」组(上限10、默认),老用户回填、新注册自动绑定
- 并发计数改用 Redis(自愈 sorted-set + TTL + fail-open):
  · 用户并发(画图台 + API key 合计)受其分组上限限制,0=不限制 → 超返回 429
  · 账号级并发也从内存 gate 换成同一套 Redis(6 处调用点)
  · 移除旧的「已有正在生成的任务」单任务锁
- 后台「并发分组」新菜单:增删改、设默认、用户数;默认组不可删(删别的组成员转默认)
- 用户管理:并发列 + 新建/编辑可选分组
- 个人设置页:账户信息卡(用户名/邮箱/角色/余额/并发);/me 暴露 concurrency_group/limit

品牌 / Logo(上传到 RustFS):
- Logo 改成拖拽/点击上传,点保存才上传;替换自动删旧;branding/ 设为公开且被清理任务 pin 住(永不删)
- 有自定义就用:前台左侧 nav + 后台侧栏 + favicon(浏览器标签);没有则默认 V 图标
- 前台页头还原成文字;首页 Hero 子标题用 site.subtitle(默认那句宣传语,设置页预填)
- 邮件验证码标题用站点名;新增 POST/DELETE /settings/logo + POST /settings/asset(首页底图上传)

兑换码开关:
- 系统设置→积分 新增「开启兑换码」(默认开);关闭后后端拒绝兑换、前台隐藏兑换入口(/site 暴露 cdk_redeem_enabled)

文档 / 分辨率:
- 去掉 quality 参数:size(宽x高)同时决定比例 + 分辨率档(长边映射 1K/2K/4K)
- 文档加「分辨率对照表」(14 个比例 × 1K/2K/4K → size 该传的值);guessRatio 与自定义模型 RATIO_OPTS 对齐到 14 个

其它:
- 删模型时同步清掉各上游账号「支持模型」里的该 id
- 首页设置/兑换码弹窗去固定高度滚动条;展示位弹窗浅色主题适配

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

backend/internal/http/handler/admin_read.go

@@ -182,6 +182,7 @@ func userPublic(user model.User) gin.H {
 		"status":         user.Status,
 		"credits":        user.Credits,
 		"notes":          user.Notes,
+		"concurrency_group_id": user.ConcurrencyGroupID,
 		"created_at":     unixSec(user.CreatedAt),
 		"last_login_at":  unixSecPtr(user.LastLoginAt),
 		"last_login_ip":  user.LastLoginIP,

backend/internal/http/handler/app_settings.go

@@ -1,7 +1,9 @@
 package handler
 
 import (
+	"encoding/base64"
 	"net/http"
+	"strings"
 
 	"backend/internal/service"
 	"github.com/gin-gonic/gin"
@@ -15,6 +17,87 @@ func NewAppSettingsHandler(settings *service.AppSettingsService) *AppSettingsHan
 	return &AppSettingsHandler{settings: settings}
 }
 
+// LogoUpload stores a base64 image as the site logo in RustFS (deleting the old
+// one) and persists site.logo. Called on 保存 — not on file pick.
+func (h *AppSettingsHandler) LogoUpload(c *gin.Context) {
+	var body struct {
+		Data        string `json:"data"` // base64, optionally a "data:...;base64," URL
+		ContentType string `json:"content_type"`
+	}
+	if err := c.ShouldBindJSON(&body); err != nil {
+		c.JSON(http.StatusBadRequest, gin.H{"detail": "invalid request body"})
+		return
+	}
+	raw := strings.TrimSpace(body.Data)
+	if strings.HasPrefix(raw, "data:") {
+		if i := strings.Index(raw, ","); i >= 0 {
+			if body.ContentType == "" {
+				meta := raw[5:i] // e.g. image/png;base64
+				if j := strings.Index(meta, ";"); j >= 0 {
+					body.ContentType = meta[:j]
+				}
+			}
+			raw = raw[i+1:]
+		}
+	}
+	data, err := base64.StdEncoding.DecodeString(raw)
+	if err != nil {
+		c.JSON(http.StatusBadRequest, gin.H{"detail": "图片解码失败"})
+		return
+	}
+	url, err := h.settings.UploadLogo(c.Request.Context(), data, body.ContentType)
+	if err != nil {
+		c.JSON(http.StatusBadRequest, gin.H{"detail": err.Error()})
+		return
+	}
+	c.JSON(http.StatusOK, gin.H{"ok": true, "logo": url})
+}
+
+// AssetUpload stores a public image (homepage 底图 etc.) in RustFS and returns
+// its storage path for the caller to save (e.g. as a showcase card's image).
+func (h *AppSettingsHandler) AssetUpload(c *gin.Context) {
+	var body struct {
+		Data        string `json:"data"`
+		ContentType string `json:"content_type"`
+	}
+	if err := c.ShouldBindJSON(&body); err != nil {
+		c.JSON(http.StatusBadRequest, gin.H{"detail": "invalid request body"})
+		return
+	}
+	raw := strings.TrimSpace(body.Data)
+	if strings.HasPrefix(raw, "data:") {
+		if i := strings.Index(raw, ","); i >= 0 {
+			if body.ContentType == "" {
+				meta := raw[5:i]
+				if j := strings.Index(meta, ";"); j >= 0 {
+					body.ContentType = meta[:j]
+				}
+			}
+			raw = raw[i+1:]
+		}
+	}
+	data, err := base64.StdEncoding.DecodeString(raw)
+	if err != nil {
+		c.JSON(http.StatusBadRequest, gin.H{"detail": "图片解码失败"})
+		return
+	}
+	path, err := h.settings.UploadAsset(c.Request.Context(), data, body.ContentType)
+	if err != nil {
+		c.JSON(http.StatusBadRequest, gin.H{"detail": err.Error()})
+		return
+	}
+	c.JSON(http.StatusOK, gin.H{"ok": true, "path": path})
+}
+
+// LogoDelete removes the uploaded logo and falls back to the built-in default.
+func (h *AppSettingsHandler) LogoDelete(c *gin.Context) {
+	if err := h.settings.RemoveLogo(c.Request.Context()); err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"detail": "failed to remove logo"})
+		return
+	}
+	c.JSON(http.StatusOK, gin.H{"ok": true, "logo": ""})
+}
+
 func (h *AppSettingsHandler) RegistrationGet(c *gin.Context) {
 	data, err := h.settings.Registration(c.Request.Context())
 	if err != nil {

backend/internal/http/handler/concurrency_group.go

@@ -0,0 +1,80 @@
+package handler
+
+import (
+	"errors"
+	"net/http"
+
+	"backend/internal/service"
+	"github.com/gin-gonic/gin"
+)
+
+type ConcurrencyGroupHandler struct {
+	svc *service.ConcurrencyGroupService
+}
+
+func NewConcurrencyGroupHandler(svc *service.ConcurrencyGroupService) *ConcurrencyGroupHandler {
+	return &ConcurrencyGroupHandler{svc: svc}
+}
+
+func (h *ConcurrencyGroupHandler) List(c *gin.Context) {
+	items, err := h.svc.List(c.Request.Context())
+	if err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"detail": "failed to load concurrency groups"})
+		return
+	}
+	c.JSON(http.StatusOK, gin.H{"data": items})
+}
+
+func (h *ConcurrencyGroupHandler) Create(c *gin.Context) {
+	var body struct {
+		Name           string `json:"name"`
+		MaxConcurrency int    `json:"max_concurrency"`
+	}
+	if err := c.ShouldBindJSON(&body); err != nil {
+		c.JSON(http.StatusBadRequest, gin.H{"detail": "invalid request body"})
+		return
+	}
+	g, err := h.svc.Create(c.Request.Context(), body.Name, body.MaxConcurrency)
+	if err != nil {
+		c.JSON(http.StatusBadRequest, gin.H{"detail": err.Error()})
+		return
+	}
+	c.JSON(http.StatusOK, gin.H{"ok": true, "id": g.ID})
+}
+
+func (h *ConcurrencyGroupHandler) Update(c *gin.Context) {
+	var body struct {
+		Name           *string `json:"name"`
+		MaxConcurrency *int    `json:"max_concurrency"`
+	}
+	if err := c.ShouldBindJSON(&body); err != nil {
+		c.JSON(http.StatusBadRequest, gin.H{"detail": "invalid request body"})
+		return
+	}
+	g, err := h.svc.Update(c.Request.Context(), c.Param("id"), body.Name, body.MaxConcurrency)
+	if err != nil {
+		c.JSON(http.StatusBadRequest, gin.H{"detail": err.Error()})
+		return
+	}
+	c.JSON(http.StatusOK, gin.H{"ok": true, "id": g.ID})
+}
+
+func (h *ConcurrencyGroupHandler) SetDefault(c *gin.Context) {
+	if err := h.svc.SetDefault(c.Request.Context(), c.Param("id")); err != nil {
+		c.JSON(http.StatusBadRequest, gin.H{"detail": err.Error()})
+		return
+	}
+	c.JSON(http.StatusOK, gin.H{"ok": true})
+}
+
+func (h *ConcurrencyGroupHandler) Delete(c *gin.Context) {
+	if err := h.svc.Delete(c.Request.Context(), c.Param("id")); err != nil {
+		if errors.Is(err, service.ErrNotFound) {
+			c.JSON(http.StatusNotFound, gin.H{"detail": "分组不存在"})
+			return
+		}
+		c.JSON(http.StatusBadRequest, gin.H{"detail": err.Error()})
+		return
+	}
+	c.JSON(http.StatusOK, gin.H{"ok": true})
+}

backend/internal/http/handler/site.go

@@ -23,9 +23,10 @@ func (h *SiteHandler) Public(c *gin.Context) {
 	}
 	ctx := c.Request.Context()
 	c.JSON(http.StatusOK, gin.H{
-		"title":    title,
-		"logo":     h.site.Logo(ctx),
-		"subtitle": h.site.Subtitle(ctx),
-		"contact":  h.site.Contact(ctx),
+		"title":              title,
+		"logo":               h.site.Logo(ctx),
+		"subtitle":           h.site.Subtitle(ctx),
+		"cdk_redeem_enabled": h.site.CDKRedeemEnabled(ctx),
+		"contact":            h.site.Contact(ctx),
 	})
 }

backend/internal/http/handler/site_settings.go

@@ -35,7 +35,6 @@ func (h *SiteSettingsHandler) Put(c *gin.Context) {
 	ctx := c.Request.Context()
 	var body struct {
 		Title    string          `json:"title"`
-		Logo     string          `json:"logo"`
 		Subtitle string          `json:"subtitle"`
 		Contact  service.Contact `json:"contact"`
 	}
@@ -53,8 +52,8 @@ func (h *SiteSettingsHandler) Put(c *gin.Context) {
 		c.JSON(http.StatusInternalServerError, gin.H{"detail": "failed to save site settings"})
 		return
 	}
-	if err := h.site.SetBranding(ctx, body.Logo, body.Subtitle); err != nil {
-		c.JSON(http.StatusInternalServerError, gin.H{"detail": "failed to save branding"})
+	if err := h.site.SetSubtitle(ctx, body.Subtitle); err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"detail": "failed to save subtitle"})
 		return
 	}
 	if err := h.site.SetContact(ctx, body.Contact); err != nil {

backend/internal/http/handler/user_generation.go

@@ -80,7 +80,7 @@ func (h *UserGenerationHandler) Generate(c *gin.Context) {
 			c.JSON(http.StatusServiceUnavailable, gin.H{"detail": err.Error()})
 		case errors.Is(err, service.ErrProviderQuota):
 			c.JSON(http.StatusTooManyRequests, gin.H{"detail": err.Error()})
-		case errors.Is(err, service.ErrConcurrencyFull):
+		case errors.Is(err, service.ErrConcurrencyFull), errors.Is(err, service.ErrUserConcurrencyFull):
 			c.JSON(http.StatusTooManyRequests, gin.H{"detail": err.Error()})
 		case errors.Is(err, service.ErrProviderExecution):
 			c.JSON(http.StatusBadGateway, gin.H{"detail": err.Error()})
@@ -136,7 +136,7 @@ func (h *UserGenerationHandler) Test(c *gin.Context) {
 			c.JSON(http.StatusBadRequest, gin.H{"detail": err.Error()})
 		case errors.Is(err, service.ErrProviderQuota):
 			c.JSON(http.StatusTooManyRequests, gin.H{"detail": err.Error()})
-		case errors.Is(err, service.ErrConcurrencyFull):
+		case errors.Is(err, service.ErrConcurrencyFull), errors.Is(err, service.ErrUserConcurrencyFull):
 			c.JSON(http.StatusTooManyRequests, gin.H{"detail": err.Error()})
 		case errors.Is(err, service.ErrNoProviderAccount):
 			c.JSON(http.StatusServiceUnavailable, gin.H{"detail": err.Error()})

backend/internal/http/handler/v1.go

@@ -72,7 +72,6 @@ func (h *V1Handler) ImageGenerations(c *gin.Context) {
 		Prompt:  body.Prompt,
 		N:       body.N,
 		Size:    body.Size,
-		Quality: body.Quality,
 		BaseURL: requestBaseURL(c),
 	})
 	if err != nil {
@@ -110,7 +109,6 @@ func (h *V1Handler) ImageEdits(c *gin.Context) {
 		Prompt:          c.PostForm("prompt"),
 		N:               n,
 		Size:            c.PostForm("size"),
-		Quality:         c.PostForm("quality"),
 		ReferenceImages: refs,
 		BaseURL:         requestBaseURL(c),
 	})
@@ -336,7 +334,7 @@ func (h *V1Handler) writeV1Error(c *gin.Context, err error, payload map[string]a
 		c.JSON(http.StatusUnauthorized, gin.H{"detail": err.Error()})
 	case errors.Is(err, service.ErrProviderTemporary):
 		c.JSON(http.StatusServiceUnavailable, gin.H{"detail": err.Error()})
-	case errors.Is(err, service.ErrConcurrencyFull):
+	case errors.Is(err, service.ErrConcurrencyFull), errors.Is(err, service.ErrUserConcurrencyFull):
 		c.JSON(http.StatusTooManyRequests, gin.H{"detail": err.Error()})
 	case errors.Is(err, service.ErrVideoJobNotFound):
 		c.JSON(http.StatusNotFound, gin.H{"detail": err.Error()})