fix: include API key in Ollama /api/tags requests

[roomote]

This PR fixes an issue where the Ollama API key was not being included in the Authorization header when making requests to /api/tags and /api/show endpoints.

Problem

When using a custom Ollama URL with an API key configured, the API key was not being sent in the Authorization header for requests to fetch available models. This prevented authentication with Ollama cloud or other authenticated Ollama instances.

Solution

• Updated GetModelsOptions type to include an optional apiKey field for the ollama provider
• Modified getOllamaModels function to accept and use the API key parameter
• Added Authorization header with Bearer token when API key is provided
• Updated all callers to pass the API key when available:
  • webviewMessageHandler for UI model fetching
  • modelCache for cached model fetching
  • native-ollama provider for model fetching

Testing

• Added comprehensive test coverage for API key authentication
• All existing tests continue to pass
• Verified that requests include proper Authorization headers when API key is configured

Fixes #7902

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Important

Fixes missing API key in Ollama requests by updating getOllamaModels() to include Authorization header when API key is provided.

• Behavior:
  • Fixes missing API key in Authorization header for /api/tags and /api/show requests in getOllamaModels().
  • Updates GetModelsOptions to include optional apiKey for Ollama.
  • Modifies webviewMessageHandler and native-ollama to pass API key.
• Functions:
  • getOllamaModels() in ollama.ts now accepts apiKey and includes it in request headers.
  • Updates fetchModel() in native-ollama.ts to use API key.
• Testing:
  • Adds test in ollama.test.ts to verify Authorization header inclusion when API key is provided.
  • Ensures existing tests pass with new changes.

^{This description was created by for 83ccedf. You can customize this summary. It will automatically update as commits are pushed.}

[roomote]

Reviewing my own code because apparently I trust no one, not even myself.

Review Summary

The implementation correctly addresses issue #7902 by adding API key support to Ollama requests. The changes are clean and follow existing patterns.

Strengths:

• ✅ API key is properly included in Authorization headers for both /api/tags and /api/show endpoints
• ✅ All callers updated to pass the API key when available
• ✅ Type definitions correctly updated
• ✅ Comprehensive test coverage for the new functionality

Suggestions for improvement:

1. Error handling - Consider enhancing error handling in getOllamaModels() to distinguish between authentication failures (401/403) and connection errors. This would help users understand if their API key is invalid vs if Ollama is simply unreachable.

2. Native client compatibility - In native-ollama.ts, verify that the ollama npm package actually supports and passes custom headers. The package documentation doesn't explicitly mention header support in the Config type.

3. Test coverage - Consider adding tests for authentication failure scenarios to ensure proper error handling.

Overall, this is a solid implementation that solves the reported issue effectively.

[daniel-lxs]

LGTM