Add usage-based business plan types (#15934)

## Summary
- add `self_serve_business_usage_based` and `enterprise_cbp_usage_based`
to the public/internal plan enums and regenerate the app-server + Python
SDK artifacts
- map both plans through JWT login and backend rate-limit payloads, then
bucket them with the existing Team/Business entitlement behavior in
cloud requirements, usage-limit copy, tooltips, and status display
- keep the earlier display-label remap commit on this branch so the new
Team-like and Business-like plans render consistently in the UI

## Testing
- `just write-app-server-schema`
- `uv run --project sdk/python python
sdk/python/scripts/update_sdk_artifacts.py generate-types`
- `just fix -p codex-protocol -p codex-login -p codex-core -p
codex-backend-client -p codex-cloud-requirements -p codex-tui -p
codex-tui-app-server -p codex-backend-openapi-models`
- `just fmt`
- `just argument-comment-lint`
- `cargo test -p codex-protocol
usage_based_plan_types_use_expected_wire_names`
- `cargo test -p codex-login usage_based`
- `cargo test -p codex-backend-client usage_based`
- `cargo test -p codex-cloud-requirements usage_based`
- `cargo test -p codex-core usage_limit_reached_error_formats_`
- `cargo test -p codex-tui plan_type_display_name_remaps_display_labels`
- `cargo test -p codex-tui remapped`
- `cargo test -p codex-tui-app-server
plan_type_display_name_remaps_display_labels`
- `cargo test -p codex-tui-app-server remapped`
- `cargo test -p codex-tui-app-server
preserves_usage_based_plan_type_wire_name`

## Notes
- a broader multi-crate `cargo test` run still hits unrelated existing
guardian-approval config failures in
`codex-rs/core/src/config/config_tests.rs`

codex-rs/app-server-protocol/schema/json/codex_app_server_protocol.v2.schemas.json

@@ -6317,7 +6317,9 @@
         "plus",
         "pro",
         "team",
+        "self_serve_business_usage_based",
         "business",
+        "enterprise_cbp_usage_based",
         "enterprise",
         "edu",
         "unknown"