Support prolite plan type (#17419)

Addresses #17353

Problem: Codex rate-limit fetching failed when the backend returned the
new `prolite` subscription plan type.

Solution: Add `prolite` to the backend/account/auth plan mappings, keep
unknown WHAM plan values decodable, and regenerate app-server plan
schemas.

codex-rs/codex-backend-openapi-models/src/models/rate_limit_status_payload.rs

@@ -65,6 +65,8 @@ pub enum PlanType {
     Plus,
     #[serde(rename = "pro")]
     Pro,
+    #[serde(rename = "prolite")]
+    ProLite,
     #[serde(rename = "free_workspace")]
     FreeWorkspace,
     #[serde(rename = "team")]
@@ -85,4 +87,6 @@ pub enum PlanType {
     Enterprise,
     #[serde(rename = "edu")]
     Edu,
+    #[serde(rename = "unknown", other)]
+    Unknown,
 }