* fix(twitter): rewrite trending from YAML to TS with DOM scraping fallback
The old REST API /i/api/2/guide.json returns 503. Replace with a TS
adapter that:
- Tries legacy guide.json API first (with proper auth headers)
- Falls back to DOM scraping via [data-testid='trend'] elements
- Filters out promoted content
- Follows the same Strategy.COOKIE pattern as timeline.ts
* fix: use 'help' instead of 'description' in Arg (matches Arg interface)
* docs(steam): add adapter documentation, update READMEs
- Create docs/adapters/browser/steam.md
- Add steam entry to README.md and README.zh-CN.md
- Fixes doc-coverage CI check (44/44)
jakevin