fix(setup): preserve provider metadata during model selection

[kshitijk4poor]

Summary

• fix the setup wizard so provider metadata written during provider selection is preserved in the in-memory model config instead of being clobbered by the final save_config(config)
• cover the regression with hermetic setup tests for the Nous API flow, the Nous OAuth keep-current-model flow, and custom endpoint switching away from an active OAuth provider
• address the fresh-install misconfiguration behind issue [Bug]: Telegram Bot not responding at all #853, where Telegram/CLI runs could end up with broken Nous routing after setup and then fail to respond correctly

Root cause

During hermes setup, provider selection updated config.yaml directly via _update_config_for_provider(...), but later the wizard saved a stale in-memory config object back to disk. That final save could drop model.provider / model.base_url (and in the OAuth keep-current path, model.default), leaving fresh installs misconfigured.

Test plan

• python -m pytest tests/hermes_cli/test_setup.py tests/test_auth_nous_provider.py tests/test_cli_provider_resolution.py tests/hermes_cli/test_config.py -q
• python -m pytest tests/ -q -k \"not vision_tools\"

Issue

Closes #853

[teknium1]

Merged via 4525933. Thanks @kshitijk4poor — thorough fix with good test coverage.

Audited the rest of the codebase for the same stale-config-overwrite pattern:

• hermes_cli/main.py: Safe — all model flow functions do fresh load_config() before save_config()
• gateway/run.py: Safe — doesn't use _update_config_for_provider or save_config for model changes
• hermes_cli/tools_config.py: Safe — never touches model config
• hermes_cli/auth.py: Safe — doesn't hold a stale config dict

The bug was fully isolated to setup.py. Your fix covers all 9 provider paths.