feat: 画图台并发重构 + 品牌定制 + 用户备注 + provider/UI 多项修复

画图台(并发出图):
- 不再锁定 UI:点「生成」开独立任务,可连续多次并发
- 结果网格一行5个、最多10张,进行中/成功/失败状态回显,刷新保留进行中
- 生图张数 1/2/3/4,各自独立计费出卡
- 点图=参考图(单张替换/多张替换末位);首尾帧模型点视频=抓末帧设为首帧,否则放大
- /logs 新增 statuses=pending,success 服务端过滤(status IN 专用 SQL)

品牌定制(设置→网站):
- 自定义 Logo 图片 + 子标题(公开页头部 + 管理侧栏)
- 邮件验证码标题改用站点名:{title} 邮箱验证码

提示词复制:
- 去掉复制按钮,点提示词文字即复制(预览/后台日志/图片管理/画图记录),统一弹「指令已复制」
- 新增 utils/clipboard.js:execCommand 回退,非安全上下文(http/IP)也能复制

用户管理:列表加「备注」列,新建/编辑可填改备注(默认空)

provider 修复:
- grok 401 正确判死封号(markTokenFailure 漏了 grok 池)
- grok 视频支持 15s
- custom 上游报错去敏感(抹掉上游 URL/IP,改英文短描述)
- custom 去掉额度耗尽锁定:429/欠费当临时错误,账号保持 active

UI/其它:
- 展示位弹窗浅色主题适配(tab 选中高亮、输入框边框)— 主题变量 + 中心补丁
- 自定义模型:时长可填任意秒数 + 15s 预设
- 首页设置/卡密弹窗去固定高度与滚动条
- 顶部菜单「记录」→「图片」
- 下线 Flow provider(代码移除)

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

backend/internal/http/handler/user_generation.go

@@ -3,6 +3,7 @@ package handler
 import (
 	"errors"
 	"net/http"
+	"strings"
 
 	"backend/internal/service"
 	"github.com/gin-gonic/gin"
@@ -176,6 +177,16 @@ func (h *UserGenerationHandler) Logs(c *gin.Context) {
 	offset := parseInt(c.Query("offset"), 0)
 	kind := c.Query("kind")
 	status := c.Query("status")
+	// statuses=pending,success → status IN (...). Used by the 画图台 grid so it can
+	// fetch exactly the rows it shows (进行中 + 成功) in one query, server-side.
+	var statuses []string
+	if s := strings.TrimSpace(c.Query("statuses")); s != "" {
+		for _, p := range strings.Split(s, ",") {
+			if p = strings.TrimSpace(p); p != "" {
+				statuses = append(statuses, p)
+			}
+		}
+	}
 	// Secure-by-default: always scope to the caller's OWN records. This endpoint
 	// serves the front-end 日志 / 创作记录 pages, so an admin viewing their personal
 	// records must NOT see other users' work. Only an admin who explicitly opts
@@ -195,7 +206,7 @@ func (h *UserGenerationHandler) Logs(c *gin.Context) {
 	// rows with real media (success + stored file), not failed/pending events.
 	hasFile := c.Query("has_file") == "1" || c.Query("has_file") == "true"
 
-	items, total, stats, err := h.admin.Logs(c.Request.Context(), limit, offset, kind, status, nil, userID, excludeSource, source, hasFile)
+	items, total, stats, err := h.admin.Logs(c.Request.Context(), limit, offset, kind, status, statuses, nil, userID, excludeSource, source, hasFile)
 	if err != nil {
 		c.JSON(http.StatusInternalServerError, gin.H{"detail": "failed to load logs"})
 		return
@@ -430,7 +441,7 @@ func (h *UserGenerationHandler) catalogEntries(c *gin.Context) ([]gin.H, error)
 			"type":                 "video",
 			"ratios":               []string{"2:3", "3:2", "1:1", "9:16", "16:9"},
 			"resolutions":          []string{"720p"},
-			"durations":            []string{"6s", "10s"},
+			"durations":            []string{"6s", "10s", "15s"},
 			"max_reference_images": 6,
 			"reference_mode":       "asset",
 			"description":          "Grok Imagine video (文/图生视频)",