Stats page: "Favorite model" is misleading — shows historical data, not current model

Description

The Stats page (/stats) shows a "Favorite model" metric (e.g., "Opus 4.6") in the Overview tab. This is computed from historical usage data (all-time token counts per model), not from the currently active model.

The problem

• The current active model is shown in the status bar (Status → Model: e.g., deepseek-v4-pro)
• The Stats page shows "Favorite model: Opus 4.6" (or whichever model has the most historical tokens)
• Users can be confused into thinking Claude Code is currently running on that model

Suggested fix

Either:

1. Rename "Favorite model" to "Most used model" or "Historical favorite model" to clarify it's based on past usage
2. Add the current active model prominently to the Stats page alongside the historical favorite
3. Show both: "Current model" and "Most used model" as separate metrics

Context

This is especially confusing when using third-party model providers — the historical favorite (from Claude.ai/API usage) may differ from the currently configured model.