[codex] Harden token refresh retry handling

[jjoonleo]

Summary

• Store both refreshed access and refresh tokens from the refresh response headers.
• Ensure queued requests are always resolved or rejected after refresh.
• Mark refresh and post-refresh retry requests to avoid recursive refresh loops.
• Add focused interceptor tests for token rotation, concurrent queued requests, retry failures, and refresh failure sign-out.

Root Cause

The token refresh flow persisted only the refreshed access token, leaving rotated refresh tokens stale. Queued request retries also swallowed retry failures, which could leave original request handlers without a clear failure path.

Validation

• flutter test test/core/dio/interceptors/token_interceptor_test.dart
• flutter analyze
• flutter test
• git diff --check

Closes #390

[github-actions]

Visit the preview URL for this PR (updated for commit 8bd3fd7):

https://ontime-c63f1--pr398-feat-implement-issue-e57leyly.web.app

_{(expires Thu, 14 May 2026 04:25:06 GMT)}

_{🔥 via Firebase Hosting GitHub Action 🌎}

_{Sign: 7d60a2eae4c4a5839220ed6a57552a3b61cce5a3}

[github-actions]

Visit the preview URL for this PR (updated for commit 8bd3fd7):

https://on-time-front-widgetbook--pr398-feat-implement-issue-02irfmfk.web.app

_{(expires Thu, 14 May 2026 04:26:04 GMT)}

_{🔥 via Firebase Hosting GitHub Action 🌎}

_{Sign: e53128a376fed0209d449279de9c0d94c83cdd8b}