fix: Route CLI sessions through batch auth helper

[krowvin]

Parent: USACE/cwms-data-api#1772

Summary

• Routes CLI CDA session initialization through the shared helper so Batch jobs can use bearer token auth and batch job context.
• Preserves explicit token, saved login, and API key precedence while adding Batch environment fallback behavior.

Validation

• Focused CLI auth and loader tests were run during the integration pass, including tests\utils\test_credentials.py and relevant command/session tests.

[krowvin]

Closing this historical M2M-related PR because the original mega-repo implementation was broken out into focused changes. The remaining machine-auth and broker work is deferred and can be revisited later through new, separately scoped PRs once the cross-repository prerequisites are ready.