worker-sdk-persistent-pressure: published PHP's SDK shutdown missed the 8-10 s window on MySQL 8.0 #728

Goal

worker-sdk-persistent-pressure passes reliably on every backend. Its "one real SDK budget expires while pressure stays held" check measures the published PHP SDK's shutdown while an independent database write lock is held, and requires 8 to 10 seconds.

Observed

• Train Rust Server train: MySQL statement closes (#714), update validation, policy-map JSON, worker history presentation #723 at 1fd9e549a, run 40069368271, job mysql-execution (mysql-8.0), step "Compare SDK temporary database pressure with declared fault limits": the published PHP target failed that check. The native and embedded records never ran, because the PHP record fails the step first.
• The same cell passed on main's three latest runs (40057998770, 40002197719, 39961767541). The train does not change this profile, its contract, the published PHP image or the SDK.
• The measured shutdown time was not printed, so it is unknown whether shutdown took under 8 s or over 10 s.

Done so far

ef5a6be70 (in #723) makes the assertion print the measured time and backend. The window is unchanged.

Next

If it recurs, the printed time shows whether the PHP reference ran past its budget under CI load or the window is too tight for the SDK's declared budget. A change to the window needs a recorded contract decision, not an edited expectation.