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/local-dev.md

@@ -0,0 +1,54 @@
+# Local development
+
+Full-stack Nuxt 4 development at the repository root. Data defaults to `./data`.
+
+## Requirements
+
+- Node.js **22**
+- npm **11** (see `packageManager` in `package.json`)
+
+## Start
+
+```bash
+npm install
+cp .env.example .env   # optional
+npm run dev
+```
+
+Open `http://localhost:3000/setup` to create the admin account. Data directory defaults to `./data` (`DATA_DIR` overrides).
+
+## Common commands
+
+| Command | Description |
+| ------- | ----------- |
+| `npm run dev` | Dev server |
+| `npm run build` | Production build |
+| `npm run start` | Run `.output` |
+| `npm run lint` | ESLint |
+| `npm run typecheck` | Type check |
+| `npm test` | Unit tests |
+| `npm run reset-password` | Reset password (optional username) |
+| `npm run migrate` | Preview legacy dir migration (`-- --apply` to run) |
+
+## Dev-only variables
+
+| Variable | Description |
+| -------- | ----------- |
+| `DEV_BYPASS_ACCESS` | `true` bypasses login (skips `/setup`; rarely needed) |
+| `DATA_DIR` | Data directory, default `./data` |
+
+Full list: [Environment variables](./configuration.md).
+
+## Dual-domain local test
+
+Edit `hosts` and follow [Dual-domain separation](./domain-separation.md) for local verification.
+
+## Documentation site
+
+```bash
+npm run docs:dev
+npm run docs:build
+npm run docs:preview
+```
+
+Sources live in `docs-site/`; screenshot sources are in `docs/screenshots/` (including `login.png`), copied to `docs-site/public/screenshots/` before build.