muster release v5.37.1

Every progress notification of a downstream call reaches the caller. mcp-go’s streamable-http server could drop a notification its forwarder had already taken when the response was written first, and sent a call’s notifications on the standalone GET stream, where they could arrive after the call’s response and be dropped by the per-call progress router. muster builds with giantswarm/mcp-go, mcp-go v1.1.1 with both fixes, until an upstream release carries them; the progress tests no longer pace the backend on delivery.