Ensure credentials are stored encrypted

Audit and ensure all sensitive credentials are properly encrypted in storage.

Context:

• Application handles GitHub tokens and session secrets
• Production security requires encrypted credential storage
• Need to verify current credential handling meets security standards

Acceptance Criteria:

• Audit current credential storage methods
• Verify GitHub tokens are properly encrypted
• Check session secret handling
• Review environment variable security
• Implement encryption for any plaintext credentials found
• Document credential security practices

Priority: High

Start by locating how GitHub tokens, session secrets, and environment variables are stored and read. Audit each path for plaintext handling and compare it with the project's existing security practices. Done means sensitive credentials are encrypted where required and the credential security practices are documented.