refactor: remove Codex credits handling from services and UI components

- Eliminated CodexCreditsSnapshot interface and related logic from CodexUsageService and UI components.
- Updated CodexUsageSection to display only plan type, removing credits information for a cleaner interface.
- Streamlined Codex usage formatting functions by removing unused credit formatting logic.

These changes simplify the Codex usage management by focusing on plan types, enhancing clarity and maintainability.

libs/types/src/codex-app-server.ts

@@ -55,7 +55,6 @@ export interface AppServerRateLimitsResponse {
 export interface AppServerRateLimits {
   primary: AppServerRateLimitWindow | null;
   secondary: AppServerRateLimitWindow | null;
-  credits?: AppServerCredits;
   planType?: string;
 }
 
@@ -65,12 +64,6 @@ export interface AppServerRateLimitWindow {
   resetsAt: number;
 }
 
-export interface AppServerCredits {
-  hasCredits: boolean;
-  unlimited: boolean;
-  balance: string;
-}
-
 /**
  * Generic JSON-RPC request structure
  */

libs/types/src/index.ts

@@ -40,7 +40,6 @@ export type {
   AppServerRateLimitsResponse,
   AppServerRateLimits,
   AppServerRateLimitWindow,
-  AppServerCredits,
   JsonRpcRequest,
   JsonRpcResponse,
 } from './codex-app-server.js';