Summary

Adds support for the latest AI models to GitLens' AI features:

• Claude Opus 4.5
• GPT-5.1

Impact

• Enables users to leverage newer, more capable AI models for commit message generation, explanations, and other AI features

Validation

• Verify Claude Opus 4.5 appears in AI model selection
• Verify GPT-5.1 appears in AI model selection
• Verify both models work correctly with AI features

Risk

Low - Additive feature adding new model options

Issue created retroactively via commit audit