uses the same logic as shimmer_spans to render the `•` spinner. on terminals without true-color support, fall back to the existing `•/◦` blinking logic. https://github.com/user-attachments/assets/19db76f2-8fa2-440d-9fde-7bed67f4c4dc
uses the same logic as shimmer_spans to render the `•` spinner. on terminals without true-color support, fall back to the existing `•/◦` blinking logic. https://github.com/user-attachments/assets/19db76f2-8fa2-440d-9fde-7bed67f4c4dc