v2.3.1

Server-card metadata: fill in description, homepage, icon, output schemas, annotations

/.well-known/mcp/server-card.json was omitting serverInfo.description/
homepage/icon and each tool's outputSchema/annotations, even
though that data already exists via MCP_WEBSITE_URL and each tool's own
@mcp.tool() registration -- it just wasn't being copied over into the
card. Filling these in is what Smithery's own quality-score dashboard
flagged as missing after publishing there.

Smithery badges

README and the landing page now link to the
Smithery listing,
alongside the existing Glama badge.