fix: taking plan type from usage endpoint instead of thru auth token (#7610)

pull plan type from the usage endpoint, persist it in session state /
tui state, and propagate through rate limit snapshots

codex-rs/protocol/src/protocol.rs

@@ -847,6 +847,7 @@ pub struct RateLimitSnapshot {
     pub primary: Option<RateLimitWindow>,
     pub secondary: Option<RateLimitWindow>,
     pub credits: Option<CreditsSnapshot>,
+    pub plan_type: Option<crate::account::PlanType>,
 }
 
 #[derive(Debug, Clone, PartialEq, Deserialize, Serialize, JsonSchema, TS)]