8c1e457150
Two defects in internal/mcp, both about a call that reports done when nothing happened. Client.call accepted a frame carrying our id and neither result nor error. The HTTP transport already refuses one; the stdio transport does not, so the refusal depended on which door the server was behind. Down that path tools/call returns an empty string and a nil error, and the act is recorded as run. Manager.ReadResource reported ErrNoServer for a server that is configured but down. Call keeps those two apart on purpose — one says the tool can never exist, the other says not right now.