Add Pro Max plan support and update Pro display names (#47971)

## What changed

- Recognize `promax` in authentication, account responses, and backend rate limits; update generated schemas and client types.
- Display `prolite` as “Pro”, `pro` as “Pro (More)”, and `promax` as “Pro (Max)” in account labels, status, and analytics.
- Include Pro Max in experimental context eligibility, paid-plan tooltips, and usage-limit guidance for purchasing credits.

## Testing

Extend coverage for Pro Max plan parsing, account and rate-limit responses, experimental context eligibility, and plan display names. Update the login token test to expect “Pro (More)”.

GitOrigin-RevId: 197e00fa7a99cbce125c8f1d43a451ec1ed5c1fb

codex-rs/protocol/src/error.rs

@@ -766,10 +766,12 @@ impl std::fmt::Display for UsageLimitReachedError {
                     retry_suffix_after_or(self.resets_at.as_ref())
                 )
             }
-            Some(PlanType::Known(KnownPlan::Pro | KnownPlan::ProLite)) => format!(
-                "You’ve hit your usage limit. Visit https://chatgpt.com/codex/settings/usage to purchase more credits{}",
-                retry_suffix_after_or(self.resets_at.as_ref())
-            ),
+            Some(PlanType::Known(KnownPlan::Pro | KnownPlan::ProLite | KnownPlan::ProMax)) => {
+                format!(
+                    "You’ve hit your usage limit. Visit https://chatgpt.com/codex/settings/usage to purchase more credits{}",
+                    retry_suffix_after_or(self.resets_at.as_ref())
+                )
+            }
             Some(PlanType::Known(
                 KnownPlan::Enterprise | KnownPlan::Edu | KnownPlan::EduPlus | KnownPlan::EduPro,
             )) => format!(