Support self-serve Business ProLite accounts (#35785)

## What changed

- Recognize `self_serve_business_prolite` across authentication, account and rate-limit APIs, generated schemas, workspace classification, status display, cloud configuration gating, and usage-limit messaging.
- Keep the Python SDK's `PlanType` enum compatible with non-empty string values introduced by newer Codex runtimes while preserving its known constants.

## Testing

- Cover token parsing, account reads and notifications, backend rate-limit mapping, workspace behavior, error formatting, and Python SDK response coercion for the new plan value.

GitOrigin-RevId: 70bc17a7c4ba4028cb10e4333cc1f2ac64da361f

codex-rs/tui/src/status/helpers.rs

@@ -219,6 +219,7 @@ mod tests {
             (PlanType::Pro, "Pro"),
             (PlanType::ProLite, "Pro Lite"),
             (PlanType::Team, "Business"),
+            (PlanType::SelfServeBusinessProLite, "Business"),
             (PlanType::SelfServeBusinessUsageBased, "Business"),
             (PlanType::Business, "Enterprise"),
             (PlanType::EnterpriseCbpUsageBased, "Enterprise"),