fix(douban): read search results from page data

[warkcod]

Summary

• fall back to window.DATA.items when Douban search result DOM is not rendered
• restore OPENCLI_CDP_ENDPOINT as an explicit CDP routing override for browser-backed commands
• add adapter/runtime tests for the fallback and CDP routing

Verification

• npm run test:adapter -- clis/douban/utils.test.js
• npx vitest run --project unit src/runtime.test.ts
• npm run build
• OPENCLI_CDP_ENDPOINT=http://127.0.0.1:9222 node dist/src/main.js douban search --type book "大棋局" --limit 3 -f json

[warkcod]

Closed because this fix should target upstream jackwener/OpenCLI instead. Upstream PR: jackwener#1213