feat(cli): include cache tokens in stats

[bold84]

Summary

• include cache read/write tokens in per-model stats output
• include cache tokens in avg/median session calculations

Testing

• bun turbo typecheck

Issue

• Fixes stats: include cache tokens in averages #10581

[github-actions]

The following comment was made by an LLM, it may be inaccurate:

Based on my search, I found the following potentially related PRs:

1. PR feat: display Google Gemini cached token stats #6860: feat: display Google Gemini cached token stats

   • Related: Also adds cached token statistics display functionality

2. PR feat: add /stats dialog with token usage statistics #10234: feat: add /stats dialog with token usage statistics

   • Related: Adds token usage statistics display (may overlap with cache token stats feature)

3. PR feat(opencode): add /context usage dialog #10576: feat(opencode): add /context usage dialog

   • Potentially related: Appears to be another recent stats/usage feature in the CLI

These PRs may address similar or overlapping functionality around displaying cache and token statistics. PR #10234 in particular appears most directly related since it implements stats dialog with token usage. You may want to review these to ensure there's no duplication of effort.