Streaming chat outputs raw thinking tokens — poor UX #148

Summary

mmx text chat in streaming mode currently dumps raw thinking tokens to the terminal as they arrive. This is:

1. Noisy — thinking text is often verbose, stream-of-consciousness content that the user doesn't need to see
2. Visually disruptive — the thinking output interspersed with the response text creates a cluttered terminal
3. Bad for piping — thinking content mixes into stdout output

Proposed solution

Replace raw thinking output with a dynamic animated indicator:

• Cycling braille spinner (⠋ ⠙ ⠹ ⠸ ⠼ ⠴ ⠦ ⠧ ⠇ ⠏) at 12.5 fps
• "Thinking (Xs)" label with real-time elapsed counter
• Hue-rotating truecolor ANSI colors on both spinner and label for a smooth, continuous animation
• Renders via \r (carriage return) on stderr, keeping stdout clean
• Automatically clears and transitions to "Response:" when thinking ends

See linked PR.