release: v1.2.1 — login captcha, docs site, and bug fixes

Add slider captcha for web login, VitePress documentation on GitHub Pages,
and fixes for gallery delete refresh, pagination jump, and copy-format persistence.

docs-site/en/guide/configuration.md

@@ -0,0 +1,101 @@
+# Environment variables
+
+Configure PicHost via environment variables (Docker / `.env`) or the in-app **Settings** page. Most values prefer **SQLite** when saved; some env vars override or lock UI editing.
+
+## Priority overview
+
+| Setting | Priority (high → low) | Env overrides UI |
+| ------- | --------------------- | ---------------- |
+| API upload token | Env → SQLite | **Yes** (cannot regenerate in UI) |
+| WebP quality | SQLite → env → default 80 | No |
+| Referer whitelist | SQLite → env | No |
+| Site / image base URL | SQLite → env → request origin | No |
+| Hide `images/` prefix | SQLite → env → default false | No |
+| Date-based paths | SQLite → env → default true | No |
+| Global auto-delete days | SQLite → env → default 0 | No |
+
+## Variables
+
+### `API_UPLOAD_TOKEN`
+
+Token for external uploads (Twikoo, userscripts, blogs). Header: `Auth-Token: <token>`; form field `token` still works.
+
+- Generate in **API** page when unset
+- **When set in env, it wins** — UI shows “overridden by environment” and cannot regenerate
+- Alias: `NUXT_API_UPLOAD_TOKEN`
+
+### `ALLOWED_REFERER_HOSTS`
+
+Comma-separated Referer whitelist. Own hostnames are allowed automatically. Optional; configurable in Settings.
+
+### `SITE_BASE_URL` / `IMAGE_BASE_URL`
+
+- **Site URL**: admin UI, API, Twikoo upload
+- **Image URL**: copied links and public image URLs
+
+Single-domain: set `IMAGE_BASE_URL` only or leave empty (request origin). Dual-domain: hostnames must differ — see [Dual-domain separation](./domain-separation.md). Values must match proxy `server_name`; do not use `localhost`, IP, or unlisted hostnames for production admin access.
+
+### `HIDE_FOLDER_IN_URL`
+
+`true` hides the `images/` prefix in public URLs.
+
+### `STORAGE_USE_DATE_PATH` / `STORAGE_LAYOUT`
+
+- `true` or `STORAGE_LAYOUT=date` (default): `images/YYYY/MM/id.webp`
+- `false` or `STORAGE_LAYOUT=flat`: `images/id.webp`
+
+Also toggled in Settings.
+
+### `DATA_DIR`
+
+Root for images and SQLite. Default `./data`; `/data` in container.
+
+### `WEBP_QUALITY`
+
+Server WebP quality 1–100, default **80**.
+
+### `AUTO_DELETE_DAYS`
+
+Delete images older than N days globally; `0` disables. Affects **new uploads after enable** only. Also in Settings.
+
+### `DEV_BYPASS_ACCESS`
+
+Local dev only: `true` bypasses login. Never use in production.
+
+### Storage backends (optional)
+
+Admins usually add backends in **Storage** UI; env vars such as `STORAGE_BACKEND=s3` and `S3_*` are also supported. See [Storage](./storage.md).
+
+## Docker Compose example
+
+```yaml
+services:
+  pichost:
+    image: muxui/pichost:latest
+    ports:
+      - "6892:6892"
+    volumes:
+      - ./data:/data
+    environment:
+      SITE_BASE_URL: https://admin.example.com
+      IMAGE_BASE_URL: https://pic.example.com
+      API_UPLOAD_TOKEN: your-secret-token
+      WEBP_QUALITY: "85"
+```
+
+Restart the container after changing env vars.
+
+## Settings mapping
+
+| In-app setting | Environment variable |
+| -------------- | ---------------------- |
+| API token | `API_UPLOAD_TOKEN` |
+| Referer protection | `ALLOWED_REFERER_HOSTS` |
+| Site URL | `SITE_BASE_URL` |
+| Image URL | `IMAGE_BASE_URL` |
+| Hide folder prefix | `HIDE_FOLDER_IN_URL` |
+| Date-based paths | `STORAGE_USE_DATE_PATH` / `STORAGE_LAYOUT` |
+| WebP quality | `WEBP_QUALITY` |
+| Auto-delete | `AUTO_DELETE_DAYS` |
+
+Template: [`.env.example`](https://github.com/O96u/PicHost/blob/main/.env.example) in the repo root.