## Summary
Three fixes to the run-ops database split (the Cloud-only mode where
run-lifecycle rows live on a dedicated Postgres). All are inert in the
default single-database deployment.
The main fix: on the batch trigger paths, a parentless batch's item runs
chose their physical store from a fresh per-org mint-flag read at
processing time, so flipping an org's flag mid-batch could land an item
in a different store than its batch, breaking the `TaskRun.batchId`
foreign key (or silently orphaning the item). The other two harden the
split's safety nets: the schema-parity test now actually compares
columns, and the read fan-out gate now signals when it has been silently
disabled.
## Batch item residency
`RunEngineBatchTriggerService` (api.v2) and the BatchQueue item callback
(api.v3) now anchor each item's id mint on the batch's own friendlyId,
mirroring the already-safe `BatchTriggerV3Service`. Residency is a pure
id-shape check, so an item can no longer diverge from its batch across a
mid-batch flag flip. The pre-failed-run fallback is anchored the same
way (it also sets `batchId`), and the shared mint branch is consolidated
into one helper so every mint path stays in lockstep. No new database
queries; single-database mode is unchanged (a cuid-shaped batch
friendlyId yields a cuid item).
## Schema parity test
The parity test previously read only the dedicated schema and matched
model headers with regexes, so it never compared columns and could not
catch a run-subgraph column that diverged between the two physical
schemas. It now parses both schemas and asserts bidirectional
scalar-column parity (type, nullability, array-ness, default) across the
run-subgraph models, and fails on any field line it can't parse. Scoped
to the run-subgraph models so unrelated control-plane edits don't break
it.
## Read fan-out signal
The split read fan-out gate is decided by the object identity of the NEW
vs control-plane clients. It now warns when both run-ops URLs are set
but the NEW client isn't a distinct instance (fan-out silently off), and
a new test exercises the real topology-into-gate wiring so a future
refactor that aliases the clients can't disable fan-out unnoticed.
## Verification
New unit and glue tests cover all three changes; the DB-backed
residency, store-routing, and topology suites pass against real
Postgres; `typecheck` is clean for both packages.
Daniel Sutton
d59743bd35