Three owner-requested polish changes:
- robot: replace the lengthening 60-90 min -> 6 h proactive-nudge ramp with a
flat uniform 9-12 h wait before every nudge; the existing sleep-window gate
still skips and defers a nudge that would land in the robot's night.
- ui: colour the lobby/in-game unread dot by type -- the regular danger colour
when a chat message is unread, a softer amber (--warn) when only nudges are.
Adds a per-viewer unread_messages flag (chat_messages.kind='message') across
the backend DTO, FlatBuffers wire, gateway transcode and the UI store.
- ui: float games with any unread notification to the top of the lobby's
your-turn and opponent-turn sections (finished keeps its order), reusing the
existing unread_chat flag.
Docs (ARCHITECTURE 7, FUNCTIONAL + _ru) updated. No DB migration; the new wire
field is backward-compatible.