Build the per-session plain-GET eligibility predicate a standalone GET
stream registers with the push channel, bound to the session's resolved
ConnectionState. The Streamable HTTP transport supplies this when opening
the GET stream so notifications/resources/updated delivery consults the
listener's own per-session subscriptions (keyed on Mcp-Session-Id) instead
of the shared fallback connection.
Build the per-session plain-GET eligibility predicate a standalone GET stream registers with the push channel, bound to the session's resolved ConnectionState. The Streamable HTTP transport supplies this when opening the GET stream so notifications/resources/updated delivery consults the listener's own per-session subscriptions (keyed on Mcp-Session-Id) instead of the shared fallback connection.