fix(cli): add DeepSeek to model picker and setup

[helix4u]

What does this PR do?

Adds DeepSeek to the interactive provider picker used by hermes model and aligns setup's fallback provider model list with that support.

DeepSeek was already supported in provider auth/config and model metadata, but it was not selectable from the interactive model flow. This made the CLI picker and setup flow inconsistent with the rest of the codebase.

Related Issue

Fixes https://discord.com/channels/1053877538025386074/1490477898040082585/1490477898040082585

Type of Change

• Bug fix
• Tests

Changes Made

• Added deepseek to the provider label map in hermes_cli/main.py
• Added DeepSeek to the interactive provider selection list in hermes_cli/main.py
• Routed DeepSeek through the existing API-key provider flow in hermes_cli/main.py
• Added DeepSeek to _DEFAULT_PROVIDER_MODELS in hermes_cli/setup.py
• Added a regression test in tests/test_model_picker_deepseek.py

How to Test

1. Run hermes model and verify DeepSeek appears in the provider picker.
2. Select DeepSeek and verify the CLI enters the API-key provider flow.
3. Run source venv/bin/activate && python -m pytest tests/test_model_picker_deepseek.py tests/hermes_cli/test_setup.py tests/hermes_cli/test_setup_model_provider.py tests/test_model_provider_persistence.py tests/test_cli_provider_resolution.py -q.

Screenshots / Logs

• Focused validation passed: 47 passed in 5.66s
• Tested on Linux

[kshitijk4poor]

Thanks for the PR — DeepSeek has since been fully integrated on main via the CANONICAL_PROVIDERS refactor (#9237). It's now in hermes_cli/models.py as a first-class provider with a full model list (deepseek-chat, deepseek-reasoner, deepseek-v3.2, etc.), and routes through the _model_flow_api_key_provider path in main.py.

This PR predates that work so it's now superseded. Closing — thanks for being ahead of the curve on this one!