The lifecycle-column-census test file spawned the census CLI ~14 times, each
parsing every tracked source file to a TypeScript AST (~2s for ~1960 files).
Many spawns were byte-identical, deterministic, read-only real-repo scans:
the --json census 4x, the plain report 2x, plus a repeated identical
--update-baseline tree-sync across the ratchet cases. Memoize each distinct
read-only spawn's output (keyed by argv) and reuse the synced baseline JSON,
collapsing duplicate full-AST scans without changing any assertion.
File wall-time: 30.5s -> 18.6s (-39%). 57/57 tests still pass.
Fusion-Task-Id: FN-slow-test-census
911b7f1c31