Extract the dashboard-layout optimistic-concurrency mechanism (issue #581)
into a shared server helper (takeBaseToken plus guardedUserUpdate /
guardedRowUpdate) and a client helper (readUpdatedAtToken, withBaseToken,
isConflict). Retrofit the dashboard-widgets route onto the helper and apply the
same guard to the insights layout, medications layout, and coach about-me write
endpoints.
A request that omits the base token keeps the byte-identical unconditional
write, so older clients are unaffected. Document the contract in the OpenAPI
registry, including the dashboard-widgets path that was previously absent.
Marc-André Bombeck