release: v1.4.0 — 标签系统、操作日志扩展与文档截图更新

- 每用户标签与彩色打标，图库 OR/AND 筛选与批量打标
- 操作日志记录登录、删除、设置与标签操作
- API 标签/打标接口；README 与文档站截图同步

docs-site/en/guide/users-and-permissions.md

@@ -16,6 +16,7 @@ PicHost uses role-based access control (RBAC): **admin** and **user**. Enforceme
 | Global API token | ✓ | — |
 | Personal API token | ✓ | ✓ |
 | Gallery stats overview (incl. user count) | ✓ | partial |
+| Tag management (Settings → Tag management) | ✓ | — |
 | Activity log (Settings → Activity log) | ✓ | — |
 
 Regular users see **API**, **Gallery** in the nav; user menu: **Change password**, **Sign out**.
@@ -39,6 +40,20 @@ Regular users see **API**, **Gallery** in the nav; user menu: **Change password*
 - If verification is misconfigured: `docker exec pichost slider` resets to the local slider
 - Login rate limiting
 
+## Tags
+
+- Tags are **per-user**: regular users manage and filter only their own tags and images
+- After upload on the home page, **tag one image** or use **batch tagging**; the gallery supports tag filters (OR / AND) and batch tagging
+- Admins manage tags under **Settings → Tag management** (create, recolor, merge, delete). Tags classify images only and **do not change** `images/` storage paths
+
+![Batch tagging](/screenshots/tags-batch.png) ![Tag management](/screenshots/tags.png)
+
+## Activity log
+
+Admins review uploads, deletes, logins, settings changes, tag operations, and more under **Settings → Activity log**, with filters for date, user, action type, and source.
+
+![Activity log](/screenshots/logs.png)
+
 ## Upload preferences & auto-delete
 
 - **Upload preferences**: admins configure client compression and auto-copy in **Settings → Basic**; regular users can flip the home upload card for personal preferences