docs(i18n): 恢复并补齐英文版 vitepress，README 默认改为英文

- README 默认英文：README.en.md → README.md（英文为默认），中文移至 README.zh-CN.md，语言切换链接同步
- 恢复被删除的 docs/en/ 英文文档（git 历史 cc5e53c5^），删除 4 篇已废弃文件
- 英文导航 config.ts 对齐中文结构（新增 Deployment/Changelog 侧栏，同步 Guide/Design 条目）
- 翻译 15 篇中文新增文档：guide 5 篇（certificates/pages-usage/proxy-config/uptime-kuma/zone-domain-migration）+ design 10 篇（zone-design/cloudflare-pointing/waf-orchestration/origin-error-page/edge-cache-design/pages-design/logstore/kuma-design/login-captcha/observability 三篇）
- en 首页更新（新增 Pages 特性、tagline 同步）；changelog 英文入口指向中文版
- vitepress 构建验证：43 个英文页面全部渲染

注意：29 篇旧英文文档为恢复版，部分内容（如 deployment/server、reference/configuration）可能落后于中文，需后续逐篇同步

docs/en/reference/cli.md

@@ -0,0 +1,149 @@
+# CLI Commands
+
+You will learn: Common commands for starting, building, testing, installing, and uninstalling the OpenFlare Server, Admin Frontend, Agent, Swagger, and Documentation site.
+
+## Server
+
+Start from source:
+
+```bash
+cd openflare-server
+export SESSION_SECRET='replace-with-random-string'
+export SQLITE_PATH='./openflare.db'
+export LOG_LEVEL='info'
+go run .
+```
+
+Specify listening port and logging directory:
+
+```bash
+go run . --port 3000 --log-dir ./logs
+```
+
+Run tests:
+
+```bash
+cd openflare-server
+GOCACHE=/tmp/openflare-go-cache go test ./...
+```
+
+## Frontend
+
+Development:
+
+```bash
+cd openflare-server/web
+pnpm install
+pnpm dev
+```
+
+Build static assets:
+
+```bash
+cd openflare-server/web
+pnpm build
+```
+
+Linting and testing checks:
+
+```bash
+cd openflare-server/web
+pnpm lint
+pnpm typecheck
+pnpm test
+```
+
+## Agent
+
+Run from source:
+
+```bash
+cd openflare-agent
+go run ./cmd/agent -config /path/to/agent.json
+```
+
+Compile:
+
+```bash
+cd openflare-agent
+go build -o openflare-agent ./cmd/agent
+```
+
+Run tests:
+
+```bash
+cd openflare-agent
+GOCACHE=/tmp/openflare-go-cache go test ./...
+```
+
+## Relay (Server-side)
+
+Run from source:
+
+```bash
+cd openflare-relay
+go run ./cmd -config /path/to/relay.json
+```
+
+Compile:
+
+```bash
+cd openflare-relay
+go build -o openflare-relay ./cmd
+```
+
+## OpenFlared (Client-side)
+
+Run from source:
+
+```bash
+cd openflared
+go run ./cmd -config /path/to/flared.json
+```
+
+Compile:
+
+```bash
+cd openflared
+go build -o openflared ./cmd
+```
+
+## Install Agent
+
+```bash
+curl -fsSL https://raw.githubusercontent.com/Rain-kl/OpenFlare/main/scripts/install-agent.sh | bash -s -- \
+  --server-url http://your-server:3000 \
+  --agent-token YOUR_AGENT_TOKEN
+```
+
+## Uninstall Agent
+
+```bash
+curl -fsSL https://raw.githubusercontent.com/Rain-kl/OpenFlare/main/scripts/uninstall-agent.sh | bash
+```
+
+## Swagger
+
+Regenerate Swagger documentation:
+
+```bash
+go install github.com/swaggo/swag/cmd/swag@v1.16.4
+cd openflare-server
+swag init -g main.go -o docs
+```
+
+## Docs
+
+Local preview:
+
+```bash
+cd docs
+pnpm dev
+```
+
+Build:
+
+```bash
+cd docs
+pnpm build
+```