fix: restore Codex usage window reporting

[e2websolutions]

Summary

• Parse OpenAI Codex 5-hour and weekly usage window headers
• Show 5h/weekly usage and reset times in /usage again
• Restore CLI statusbar indicators for provider usage windows
• Add regression tests for Codex percent headers and x-ratelimit aliases

Test Plan

• venv/bin/python -m pytest tests/agent/test_rate_limit_tracker.py tests/cli/test_cli_status_bar.py -q
• venv/bin/ruff check agent/rate_limit_tracker.py cli.py tests/agent/test_rate_limit_tracker.py tests/cli/test_cli_status_bar.py
• git diff --check

[teknium1]

Thanks for restoring visibility into Codex limits. Current main already implements the /usage portion through the Codex account-usage API, but the status-bar portion remains absent.

Problems

• agent/account_usage.py:497-542 is now the Codex source of truth: it fetches /wham/usage and maps primary/secondary windows to Session/Weekly. Current /usage already renders tracker output at cli.py:9647-9653, then account usage at cli.py:9689-9710; adding a second Codex header representation would create parallel usage blocks when both sources are available.
• The status-bar implementation has moved to the snapshot/render flow at cli.py:4563-4653 and cli.py:5063-5127. The current snapshot has no provider-limit field, and GitHub reports this PR as conflicting.

Suggested changes

• Rework the status-bar addition around one cached account-usage representation rather than adding a second Codex-specific rate-limit model.
• Add tests for the current snapshot, text, and fragment renderers, preserving the existing Codex Session/Weekly endpoint tests in tests/agent/test_account_usage.py.

Automated hermes-sweeper review.