Code-review follow-ups on the S2 factory:
- add queryKeys.test.ts pinning every branch (bare vs param, null-segment
preservation, single-id, variadic composite spreads) — the contract the
epic exists to protect now has a test (suite 68 -> 73)
- unify feed/feedCount/facets on the `!== undefined` guard the rest of the
factory already uses (behaviour-identical for the always-truthy FeedFilters,
removes the collapse-on-null footgun)
Two findings skipped with rationale: variadic composite-key typing (heterogeneous
object/array segments make precise tuples high-effort; root centralized + shapes
now tested) and a pre-existing thread(null) no-op (unreachable in practice).
peter
ca0312d1a1