Allow use of custom providers for delegate agents.

[comalice]

What does this PR do?

This PR allows the use of custom providers for delegate agent inference.

Related Issue

Fixes #1011

Type of Change

• 🐛 Bug fix (non-breaking change that fixes an issue)
• ✨ New feature (non-breaking change that adds functionality)
• 🔒 Security fix
• 📝 Documentation update
• ✅ Tests (adding or improving test coverage)
• ♻️ Refactor (no behavior change)
• 🎯 New skill (bundled or hub)

Changes Made

Add custom provider resolution to LLM model configuration getter.

• hermes_cli/runtime_provider.py:_resolve_custom_provider, create custom provider resolver
• hermes_cli/runtime_provider.py:_get_model_config, use custom model resolver

How to Test

1. Init OpenAI API compatible inference endpoint (on localhost or local network), enable verbose logging
2. run hermes and execute an action requiring delegation
3. observe logs on API endpoint, verify inference access from hermes instance

Checklist

Code

• I've read the Contributing Guide
• My commit messages follow Conventional Commits (fix(scope):, feat(scope):, etc.)
• I searched for existing PRs to make sure this isn't a duplicate
• My PR contains only changes related to this fix/feature (no unrelated commits)
• I've run pytest tests/ -q and all tests pass
• I've added tests for my changes (required for bug fixes, strongly encouraged for features)
• I've tested on my platform:

Documentation & Housekeeping

• [N/A] I've updated relevant documentation (README, docs/, docstrings)
  Current docs suggest this configuration is possible.
• [N/A] I've updated cli-config.yaml.example if I added/changed config keys — or N/A
• [N/A] I've updated CONTRIBUTING.md or AGENTS.md if I changed architecture or workflows — or N/A
• [N/A] I've considered cross-platform impact (Windows, macOS) per the compatibility guide — or N/A
• [N/A] I've updated tool descriptions/schemas if I changed tool behavior — or N/A

[comalice]

I hope I did all the right things. Let me know if you guys need or want changes to this!

[comalice]

#1012 appears to also fix this issue. I'll leave it to the maintainers to select this or that one.