Servers emitted before #2154 always give REFUSED receipt bindings #2155

An admitted task whose mcp/server.py was emitted before #2154 ignores _meta, so its receipts carry no request context and every wrapped call records REFUSED/RECEIPT_BINDING_UNAVAILABLE. That fails closed, but nothing tells the operator to re-emit. Add a diagnostic or a re-emit step. From the #2154 review.