Autodev/Autoresearch: Native web search inside the Go binary (no external skill)

[Delqhi]

Problem

Web search is an external MCP skill (web_search_bundle). The Go binary has no native web search. If the skill is not installed or its Python/Node runtime breaks, research stops. SOTA agents (Claude, Perplexity, OpenAI) have built-in search.

What to do

1. internal/websearch/ Go package (stdlib + optional API key):
   • Search via DuckDuckGo HTML scraping (no API key needed)
   • Fallback to Serper/SearXNG if SIN_SEARCH_API_KEY configured
   • Respect robots.txt, rate-limit
2. sin_web_search MCP tool + sin_search chat tool
3. Cache results in ~/.cache/sin-code/websearch/
4. sin-code search "query" --limit 10 CLI
5. Integrate with Vane bridge as fallback

Acceptance criteria

• Native web search works without external skill
• DuckDuckGo scraping as default
• API-key fallback
• Rate-limiting and robots.txt respect
• Cache results

[Delqhi]

Implemented and pushed to main.