v2.3.3

Enable DNS-rebinding protection on the streamable-http transport

The mcp SDK ships Host/Origin header validation
(TransportSecurityMiddleware) but disables it by default unless a
deployment explicitly opts in -- this server wasn't. Flagged by an
external MCP compliance scanner (mcpdebugger.dev)
as failing the 2026 Streamable HTTP transport contract.

main()'s streamable-http path now wires up TransportSecuritySettings,
scoped to MCP_PUBLIC_URL (host + origin) -- see #11.

Dependencies

Bumps pyzotero 1.13.3 -> 1.13.4 (#9).