## Summary
- Splits the monolithic `codex-cloud-config` implementation into focused
modules.
- Keeps behavior unchanged from the preceding config bundle runtime
switch.
## Details
This is the reviewability follow-up after the lineage-preserving
migration PRs. The split separates backend transport, loader
construction, cache handling, metrics, validation, service
orchestration, and focused tests into named files.
Verification: `just fmt`; `just test -p codex-cloud-config`.
joeflorencio-openai