Add EvoLink provider profile

[EvoLinkAI]

Summary

• add EvoLink as a bundled model-provider plugin
• wire the profile through the existing provider registry with aliases and EVOLINK_* env vars
• use the stable OpenAI-compatible chat gateway (https://direct.evolink.ai/v1) and conservative fallback models
• extend provider discovery/profile tests for the new plugin

Validation

• uv run --with pytest --with pytest-xdist --with pytest-timeout pytest -q tests/providers/test_provider_profiles.py tests/providers/test_plugin_discovery.py
  • Result: 48 passed
• python3 -m py_compile plugins/model-providers/evolink/__init__.py
• git diff --check
• rg "api\.evolink\.ai|evolink/auto|gpt-5\.4|gpt-5\.5" plugins/model-providers/evolink tests/providers/test_provider_profiles.py tests/providers/test_plugin_discovery.py returned no matches