Support Edu Plus and Edu Pro account plans (#39316)

## What changed

- Recognize `edu_plus` and `edu_pro` as distinct education workspace plans across authentication, backend rate-limit mapping, and app-server account schemas.
- Include both plans in cloud configuration eligibility and use the education usage-limit behavior.
- Display the plans as `Edu Plus` and `Edu Pro` in the TUI status view.

## Testing

- Cover parsing, workspace classification, account and rate-limit responses, cloud configuration eligibility, usage-limit messages, and TUI display names for the new variants.

GitOrigin-RevId: bf8add780ae03a3c6d10c4f4afa0da262c37928e

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

@@ -105,6 +105,10 @@ pub(crate) fn plan_type_display_name(plan_type: PlanType) -> String {
         "Enterprise".to_string()
     } else if plan_type == PlanType::ProLite {
         "Pro Lite".to_string()
+    } else if plan_type == PlanType::EduPlus {
+        "Edu Plus".to_string()
+    } else if plan_type == PlanType::EduPro {
+        "Edu Pro".to_string()
     } else {
         title_case(format!("{plan_type:?}").as_str())
     }
@@ -234,6 +238,12 @@ mod tests {
         for (plan_type, expected) in cases {
             assert_eq!(plan_type_display_name(plan_type), expected);
         }
+        insta::assert_snapshot!(
+            "education_plan_display_names",
+            [PlanType::Edu, PlanType::EduPlus, PlanType::EduPro]
+                .map(plan_type_display_name)
+                .join("\n")
+        );
     }
 
     #[test]

codex-rs/tui/src/status/snapshots/codex_tui__status__helpers__tests__education_plan_display_names.snap

@@ -0,0 +1,7 @@
+---
+source: tui/src/status/helpers.rs
+expression: "[PlanType::Edu, PlanType::EduPlus,\nPlanType::EduPro].map(plan_type_display_name).join(\"\\n\")"
+---
+Edu
+Edu Plus
+Edu Pro