## Summary

- Document that Zed-hosted Gemini models do not use Google context
caching
- Clarify that Gemini usage is billed only as input and output tokens,
with no cached-input price
- Link to Google's Vertex AI context caching and zero-data-retention
documentation for background

## Validation

- `script/generate-action-metadata`
- `mdbook build docs`

Release Notes:

- N/A