feat: 新增 cloud-artifacts 包（Cloudflare Worker HTML artifact 托管）

POST /upload 鉴权上传 HTML 到 R2 返回 hash URL，GET /<7d|30d>/<id>.html
由 Worker 代理读取并直出 text/html。R2 lifecycle rule 自动 7/30 天删除。
独立服务，不被主 CLI 引用（类似 packages/remote-control-server/ 定位）。

Co-Authored-By: glm-5.2 <zai-org@claude-code-best.win>

packages/cloud-artifacts/scripts/setup.sh

@@ -0,0 +1,30 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+BUCKET="${BUCKET:-cloud-artifacts}"
+
+echo "==> Creating R2 bucket: $BUCKET"
+npx wrangler r2 bucket create "$BUCKET" || echo "(already exists or creation deferred)"
+
+echo "==> Adding lifecycle rule: prefix '7d/' -> expire after 7 days"
+npx wrangler r2 bucket lifecycle add "$BUCKET" delete-7d "7d/" --expire-days 7 --force
+
+echo "==> Adding lifecycle rule: prefix '30d/' -> expire after 30 days"
+npx wrangler r2 bucket lifecycle add "$BUCKET" delete-30d "30d/" --expire-days 30 --force
+
+echo "==> Setting secret TOKEN (paste value, then Enter)"
+npx wrangler secret put TOKEN
+
+cat <<'NEXT'
+
+==> Done. Remaining manual steps:
+
+  1. Bind a custom domain to the Worker (POST + GET 都走 Worker，单一域名):
+       Dashboard: Workers & Pages > cloud-artifacts > Settings > Domains & Routes > Add > Custom Domain
+       填入你的 domain（如 artifacts.example.com），Cloudflare 会自动加 DNS 记录和 SSL。
+
+  2. Update wrangler.toml [vars] PUBLIC_URL 为上一步的 domain（带 https://，如 https://artifacts.example.com）。
+
+  3. Deploy:
+       bun run deploy
+NEXT