Migrate bucket quota handlers to async/await

Migrate bucketUpdateQuota and the bucket-creation seeding helpers
(seedBucketQuotaCapacity, freshStartCreateBucket, cleanUpBucket) to
async/await, using a callback trampoline so existing callers keep working.

Seed the zero metric before persisting the quota to close the fail-open
window, probe the MPU shadow bucket so a bucket with only in-progress
uploads is not seeded to zero, log seeding failures as non-fatal warnings,
and declare the promisified metadata helpers once at module scope.

Issue: CLDSRV-949
(cherry picked from commit 79c7731)

Merge branch 'improvement/CLDSRV-945/support_cross_account_rate_limit…

…ing' into q/9.3

bump to 9.4.0-preview.6

Issue: CLDSRV-897

CLDSRV-954: bump package.json to 9.4.0-preview.5

Bump package.json to 9.4.0-preview.4

Issue: CLDSRV-928

CLDSRV-941: Bump arsenal to 8.5.4 for sproxyd

CLDSRV-941: Bump version

CLDSRV-941: Bump version

CLDSRV-936 bump package version

CLDSRV-940: pin CI Node to 22.23.1 to fix node-fetch@2 premature-clos…

…e regression

Node 22.23.0 (from GitHub runner image 20260622) introduced a regression
breaking node-fetch@2: reading a response body throws 'FetchError: Premature
close' (nodejs/node#63989, node-fetch#1767), fixed in 22.23.1. CI floated
node-version '22' and so picked up the broken release on every branch, failing
the quota/rate-limit functional tooling. Pin to 22.23.1 (keeps the 22.23.0
security patches).

Note: development/9.4 has a diverged CI layout (separate lint.yaml plus 4
node-version refs in tests.yaml) that this cascade will not fully cover; pin
those 6 refs manually when bert-e raises the 9.4 cascade.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>