weekly-research workflow uses WebSearch despite only declaring web-fetch in tools AND redacts all URLs in its research

## Summary

The [`weekly-research.md`](https://github.com/githubnext/agentics/blob/main/workflows/weekly-research.md) workflow only declares `web-fetch:` in its tools block, but at runtime on the Claude engine, `WebSearch` is implicitly available as a default tool. The model then calls `WebSearch` repeatedly — which works, but produces a report full of redacted URLs, undermining the value of a research workflow.

Per the [gh-aw tools reference](https://github.github.com/gh-aw/reference/tools/#web-tools), `web-search:` requires explicit declaration for Codex but appears to be default-on for Claude. This means the workflow silently depends on engine-specific defaults rather than explicitly declaring its intent.

## Observed behavior

1. Workflow tools block declares only `web-fetch:` (no `web-search:`)
2. gh-aw correctly passes `--allowed-tools ...WebFetch...` (no `WebSearch`) to the Claude CLI
3. Claude engine makes `WebSearch` available anyway (default-on behavior)
4. Model calls `WebSearch` multiple times for research queries
5. Results contain redacted URLs — "safe" but defeats the purpose of a web research report

## Suggestions

1. **Add `web-search:` to the workflow's tools block** — makes the intent explicit, ensures cross-engine compatibility (particularly Codex where it's off by default), and signals that the search results are expected to be useful (not redacted)
2. **Address the redacted URL problem** — a research workflow that searches the web but returns redacted URLs produces output that's hard to act on. If `web-search:` is the intended tool, the results should include actionable links

## Why this matters

- Sample workflows set the pattern for the community — implicit engine-specific defaults are confusing for anyone building their own workflows
- The workflow would silently break or degrade on Codex without `web-search:` declared
- Redacted URLs in a research report undermine the workflow's stated purpose

Bắt đầu với workflows/weekly-research.md và tài liệu tham chiếu gh-aw web-tools để so sánh các công cụ được khai báo với hành vi của Claude và Codex. Chạy hoặc kiểm tra workflow trên cả hai engine, xác minh xem chức năng tìm kiếm có khả dụng hay không và các URL trong báo cáo có bị che đi hay không. Hoàn tất khi workflow khai báo rõ ràng khả năng tìm kiếm dự kiến và tạo ra các liên kết nghiên cứu có thể thực hiện được.

Do mô hình lập chỉ mục viết ra từ nội dung của issue.