* feat(aiproxy): expose catalog context window on AI models
Populate known 1M+ context windows in catalog seed data and return
context_window in AI model list/detail API responses.
* feat(aiproxy): add instance test-connectivity and set-models actions
Add provider instance test-connectivity using stored ai_key secrets,
and set-models to import selected catalog models while skipping
existing model_key rows. Register corresponding climc perform commands.
Zexi Li
9efa08e883