The 'disabled prompt compression leaves combo override requests unchanged'
integration test predates #7379 (enforceOutputTokenBudget): its 31.5k-token
body now trips the intentional pre-dispatch 400 context_length_exceeded
reject (test:integration only runs on the release-PR gate, so the red
accrued silently on the release branch). Resize the body into the
(70%-threshold, window) corridor — still proving disabled compression leaves
the request byte-identical — with a precondition locking the corridor, and
add chatcore-context-window-boundary.test.ts locking the reject path at the
integration layer (400 + context_length_exceeded + zero upstream fetches).
Red->green validated on the isolated file run.
