create_slab required ALL ALLOWED_FIELDS present, but the Review screen fills
taxonomy/content after create (CREATE.md §1). Now requires only the capture
fields (id, sku, dims, widths); the rest stay nullable for Review.
Also fixed a pre-existing off-by-one: vals re-filtered cols by 'in data',
dropping the 6 server-managed columns and under-counting bindings (19 vs 18).
Split allowed_cols/server_cols so vals always matches cols.
Verified: 9/9 slabs tests pass; live POST /slabs with the app's capture-math
payload returns 201.
Ty
c8d6d5eda0