The sharded runner computed diff selection once, then each of its 48-73
children recomputed it at module load — including, on touchfiles-diff
branches, a per-child bun subprocess evaluating the old data file (20s
timeout each). The parent now serializes {version, selected, reason} as
EVALS_SELECTION_JSON into the shard env; e2e-helpers adopts it at load.
Fail-open preserved: any parse/shape violation → ONE stderr warning +
local recompute; absent env → silent local compute (non-sharded
entrypoints unchanged). Drift test pins parent→child round-trip to
identical selection decisions plus the malformed/absent cases.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
