Emit the shared MRTR (SEP-2322) InputRequiredResult payload onto j: the
inputRequests map plus the optional top-level requestState. This is the
glue common to InputRequiredResult.toJson and CallToolResult.toJson; it
deliberately does NOT write the resultType discriminator (a CallToolResult
stamps that elsewhere), so callers add it themselves when required.
Emit the shared MRTR (SEP-2322) InputRequiredResult payload onto j: the inputRequests map plus the optional top-level requestState. This is the glue common to InputRequiredResult.toJson and CallToolResult.toJson; it deliberately does NOT write the resultType discriminator (a CallToolResult stamps that elsewhere), so callers add it themselves when required.