Follow-up to PR #267 merge:
- Fix CLI syntax: -k is keywords, -m is max results (was reversed)
- Add clear trigger condition: use only when web_search tool unavailable
- Remove misleading curl fallback (DuckDuckGo Instant Answer API is not
a web search endpoint)
- Fix package name: ddgs (renamed from duckduckgo-search)
- Add workflow section for search → web_extract pipeline
- Add pitfalls and limitations sections
- Fix author attribution to actual contributor
- Rewrite shell script as simple ddgs wrapper with availability check
