### Fixes

- DM screen: tuned the gap above the input bar so the last message sits at a comfortable middle distance (not too tight, not floating too high)
- DM screen: the keyboard now stays open after sending a message (Instagram/WhatsApp style) — it only dismisses when you tap elsewhere, instead of closing on every send
- DM info sheet: the partner avatar now renders correctly for users with a default/list avatar (not just custom photo uploads), using the same avatar component as the header. The chevron now sits inline right next to the name
- DM info sheet: tapping a shared image now opens the same full-screen viewer as in the chat (rounded corners + save button) instead of doing nothing behind the sheet

### Changes

- DM chat background is now always the clean solid style (white in light mode, black in dark) — removed the per-chat background picker again for simplicity
- DM voice notes restyled to Instagram-style waveforms: incoming notes have black bars on a light grey bubble, your own notes have white bars on a mint-green bubble. While playing, the upcoming part dims to grey and fills back in as it progresses