Per-subsystem invariants for the eight ported sites (relay outbox claim,
lightpanda reaper, write-approval pending store, spawn_tree list/load,
local-runtime manifest, A2A conversation replay, batch runner scans,
trajectory compressor entry), trimmed from PR #114241's test hunks to at most
two per subsystem (batch_runner's dataset-load and resume-scan cases collapsed
into one). Each was red on the previous head of this branch.
(cherry picked from commit d4b54568887e69b3ee3d363ebe4dcd657ccf64f9)
72a2dae25f