feat: add zero-api-key-web-search skill

[wd041216-bit]

Summary

Adds Zero API Key Web Search — a free MCP-compatible skill for web search, page browsing, and claim verification. No API keys required. 100% free.

The skill provides 4 MCP tools:

• search_web — Live web search with support for general, news, images, videos, and books
• browse_page — Clean text extraction from any URL, stripping boilerplate
• verify_claim — Evidence-aware claim verification with verdicts and confidence scores
• evidence_report — Citation-ready structured evidence reports

Key features

• No API keys, accounts, or paid services required
• Dual-provider cross-validation (DuckDuckGo + optional SearXNG)
• Heuristic evidence classifier with 5-level verdict scale
• Works with Claude Code, Cursor, Copilot, and any MCP-compatible agent

Installation

pip install zero-api-key-web-search

MCP config

{
  "mcpServers": {
    "zero-api-key-web-search": {
      "command": "zero-mcp"
    }
  }
}

GitHub repo: https://github.com/wd041216-bit/cross-validated-search

Test plan

• Verify SKILL.md follows the template format (frontmatter + instructions)
• Confirm pip install zero-api-key-web-search installs successfully
• Run zero-mcp and verify 4 tools are exposed
• Test search_web with a sample query
• Test browse_page with a sample URL
• Test verify_claim with a sample claim
• Test evidence_report with a sample topic and claim