MCP-backed HostedToolRepository. Health-checks configured MCP
endpoints (MCP 2025-06-18 Streamable HTTP tools/list) in parallel
on a schedule, exposes the discovered tools under
namespace-sanitized callable names, applies per-endpoint
include/exclude filters, and resolves model-facing aliases to the
underlying tools. Discovery only — execution stays with the PTC
sandbox pipeline via the existing metadata contract.