[OAuth] Deploy and Test on Staging/Production Environment

[mehalyna]

• Task: Deploy the changes to the staging environment for testing.
• Steps:
  1. Ensure OAuth callbacks work in the staging environment.
  2. Verify Google/GitHub login and JWT issuance on production-like settings.
  3. Conduct final testing for the full OAuth flow.
• Deliverable: OAuth login feature verified on staging.

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US #93