release: v1.1.3 — dual-domain separation and URL options

Add admin/image domain separation with host isolation middleware,
optional hide-folder public URLs, GitHub release update check, and
Lucky/Nginx deployment docs. Switch license to GPL-3.0-only.

server/utils/image-public-path.ts

@@ -0,0 +1,13 @@
+/** 对外 URL 路径：可选去掉 key 的首段目录（如 images/） */
+export function toPublicImagePath(key: string, hideFolder: boolean): string {
+  if (!hideFolder) return key
+  const slash = key.indexOf('/')
+  return slash > 0 ? key.slice(slash + 1) : key
+}
+
+const HIDDEN_DATE_PATH_PATTERN
+  = /^\d{4}\/\d{2}\/[^/\\]+\.(jpg|jpeg|png|webp|gif|svg|ico)$/i
+
+export function isHiddenImageDatePath(path: string): boolean {
+  return HIDDEN_DATE_PATH_PATTERN.test(path)
+}