Spinner word "Contemplating" looks like "Compacting" at a glance

Problem

The spinner word "Contemplating..." looks too much like "Compacting..." when glancing at the terminal. For users who actively monitor for context compaction (and want to hand off before it hits), seeing "Contemplating" in peripheral vision triggers a false alarm every time.

Suggestion

Either:

1. Remove "Contemplating" from the spinner word rotation
2. Or let users customize the spinner word list via settings.json (e.g. a thinkingMessages array)

Option 2 would also let power users personalize their experience, which is a nice side benefit.