fix(server): preserve hub usage readings after provider rate limits#19820

Merge branch 'main' into fix/limits-hub-probe-throttle

Merge branch 'main' into fix/limits-hub-probe-throttle

Merge branch 'main' into fix/limits-hub-probe-throttle

Merge branch 'main' into fix/limits-hub-probe-throttle

Merge branch 'main' into fix/limits-hub-probe-throttle

Merge branch 'main' into fix/limits-hub-probe-throttle

Merge branch 'main' into fix/limits-hub-probe-throttle

Merge branch 'main' into fix/limits-hub-probe-throttle

Merge branch 'main' into fix/limits-hub-probe-throttle

docs(usage): explain paced hub refreshes

fix(server): keep hub usage pacing in the API

test(server): consolidate hub usage pacing coverage

Merge remote-tracking branch 'origin/main' into fix/limits-hub-probe-throttle

Merge remote-tracking branch 'upstream/main' into fix/limits-hub-probe-throttle

fix(server): a hub credential replaced with another provider gets its own reading

fix(server): hub usage reads of one account run one at a time

fix(server): hub usage readings follow the credential and survive interrupted redeems

fix(server): hub usage pacing keeps forget atomic and drops stale entries

Merge commit '4d679a63244e0f6a2118df6a6488ed1295a87797' into upstream/pr-19820-maintain

fix(server): hub Limits keep Claude accounts' bars when usage reads hit 429