v1.5.0

Upgraded to mcp 2.0.0

FastMCP was renamed to MCPServer and moved from mcp.server.fastmcp
to mcp.server; host/port/stateless_http moved from the
constructor to mcp.run()'s kwargs. Reporting our own package version
in serverInfo no longer needs the _mcp_server private-attribute
workaround, since MCPServer now takes version= directly.

Verified against the real mcp==2.0.0 package: the
OAuthAuthorizationServerProvider protocol app/oauth_provider.py
implements is unchanged, and all 139 tests pass.

No user-facing behavior change -- same tools, same OAuth flow, same
transport selection.