fix(providers): pace Codex usage fetches that bypass the quota gate

[HouMinXi]

Summary

• The status fan-out and the quota-cache refresh both read Codex usage without taking the min-interval gate that the dedicated quota fetchers use, so those paths could burst the usage endpoint.
• The Codex branch of the usage dispatcher now waits on that shared gate. A caller that already holds the gate waits at most one more interval.

Related Issues

• Closes fix(resilience): Codex usage fetches from /api/v1/me/status and the quota-cache background refresh bypass the quota-fetch throttle #15172

Validation

• Change type: other (Codex usage pacing)
• Focused tests: node --import tsx/esm --test tests/unit/codex-usage-status-throttle-15172.test.ts (2 pass)
• eslint on the changed files, with the repo suppression file
• Reconciled with release/v3.8.52 @ 23a1148486
• New test covers the change

Tests Added Or Updated

• tests/unit/codex-usage-status-throttle-15172.test.ts (added)

Coverage Notes

• One case fires four concurrent Codex usage reads on a real clock and asserts each adjacent pair starts at least one interval apart. A second case runs the auto-ping path and asserts its own gate adds at most one extra interval.

Reviewer Notes

• The interval assertion uses a real clock. A fake clock whose sleep advances time synchronously reports the wrong instant for any read that happens after the await, so an assertion on absolute timestamps from that clock is not evidence about the gate.