feat: 完善创作工作台与用户诊断支持 (#295)

* feat(canvas): 参考素材 - 增加移除按钮并删除对应连线

* feat(canvas): 完善节点面板交互与拖拽反馈

* fix(canvas): 画布交互与小地图 - 统一浮层层级并完善节点识别

* feat(prompt-optimizer): 增加 AI 提示词优化器及宿主接入

* feat(canvas): 画布 - 增加自动整理节点按钮并补充文档

* chore(web): 前端 - 修正提示词优化器格式

* chore(backend): 后端 - 修正 Go 格式检查

* feat(workspace): 完善诊断导出与本地排障支持

* chore(web): 格式化诊断导出文件

* fix(web-test): 兼容 Bun 测试运行时

* fix(web-test): 对齐模型目录协议断言

backend/internal/handler/auth.go

@@ -783,7 +783,7 @@ func shortSystemProxyPath(rawPath string) (string, string, bool) {
 // as a channel request when a business route returns 404.
 func isReservedAPIPathPrefix(value string) bool {
 	switch strings.ToLower(strings.TrimSpace(value)) {
-	case "admin", "ai", "announcements", "assets", "auth", "canvas-projects", "channels", "features", "files", "model-catalog", "models", "oauth", "plugins", "projects", "protocols", "public", "resources", "sessions", "settings", "skills", "style-profiles", "tasks", "user-data", "voice-profiles", "wallet":
+	case "admin", "ai", "announcements", "assets", "auth", "canvas-projects", "channels", "diagnostics", "features", "files", "model-catalog", "models", "oauth", "plugins", "projects", "protocols", "public", "resources", "sessions", "settings", "skills", "style-profiles", "tasks", "user-data", "voice-profiles", "wallet":
 		return true
 	default:
 		return false