## Summary
Replace stacked mobile typing rows with one animated avatar cluster and
one typing bubble. People and agents share diagonal, triangle, and
four-corner layouts, with a circular +N badge for overflow and
reduced-motion support.
Includes an opt-in local demo (`BUZZ_TYPING_PREVIEW=true`) with mixed
human/agent avatars and count controls; it never publishes typing
events.
### Related issue
Follow-up to #8505. No duplicate found in the typing-avatar PR search.
### Testing
- 3,736 mobile tests plus four unconfigured-push tests passed; analysis
and file-size checks passed.
- Installed and iterated on a physical iPhone with the existing
profile/community preserved; owner reviewed the motion and badge sizing.
Signed-off-by: kenny lopez <klopez4212@gmail.com>
Co-authored-by: Terp <5856f6900e8e0a4e0ea1f4f8d2ee33e4753d2119bc122f94ecafc660b46c0511@buzz.block.builderlab.xyz>
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