Summary

• salvage the meaningful setup-side fix from fix(setup): persist provider when switching model endpoints #951 so hermes setup no longer falls through to the generic OpenRouter/static model path when users choose Keep current
• make keep-current detection/configuration use config.model.provider and config.model.base_url, not just a few env vars, so config-backed providers are handled correctly
• add regression coverage for:
  • keep-current custom providers backed by config
  • keep-current config-backed providers using the correct provider-specific model menu
  • switching from a custom endpoint to Codex clearing the custom endpoint override and persisting the right config

Original contributor work salvaged from #951 by @StefanIsMe.

Why this salvage instead of merging #951 directly

Current main already handles most of the broader provider-persistence behavior through config-first provider resolution, so the hermes_cli/main.py env-persistence changes from #951 are largely redundant now.

The part that still matters is the setup.py keep-current normalization bug, plus some extra hardening around config-backed providers.

Test plan

• source /home/teknium/.hermes/hermes-agent/.venv/bin/activate && python -m pytest tests/hermes_cli/test_setup.py tests/hermes_cli/test_setup_model_provider.py -n0 -q
• source /home/teknium/.hermes/hermes-agent/.venv/bin/activate && python -m pytest tests/ -n0 -q