Review b1d0435c with cache, native transport, and runner coverage. Add 13 tests for source synchronization and discovery ordering, cancellation, failure and recovery, cached filters, operation reuse, address families, stopped and invalid requests, and signed values.
Three regressions intentionally fail against the current implementation: a reordered listen confirmation reports readiness before initial UPDATE values; shutdown abandons pending readiness callbacks; cancellation from another readiness callback does not suppress the canceled notification. Production behavior is unchanged.
Key partial messages by source and transaction ID, buffer bounded fragments received before their header, and avoid charging reordered requests twice against rate limits. Cover source collisions, early fragments, empty data and large values.
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>