Note remchild discovery and heartbeat notices

CURRENT.md

@@ -40,6 +40,15 @@ mobile draft at 390px.
   - [x] C11 preview caching: Discord-hosted image/GIF previews (WebP 320px, hash-addressed, 5 MiB
     cap, one attempt) run after every walk in both modes. Live run `...-20260916090722`:
     `previewed: 2`; thumbs served over `/api/media/<scrape>/<item>/thumb` (200).
+  - [x] C81 remchild discovery and heartbeat-miss notices. The server answers UDP probes on 8798
+    and beacons `{type,name,port,id}` to every interface broadcast; `remchild` with no `--server`
+    probes for 5 s, auto-connects on one answer, shows a pick list on several, and falls back to
+    the typed address on none. `--server` skips discovery. The server also watches the fast
+    heartbeat phases (10 s/30 s): a missed heartbeat sends an informational `notice` that the
+    client prints as "the connection may be unstable" — nothing else changes. Verified live:
+    discovery dedupe by beacon id, welcome + 3 ms pong, a no-heartbeat fake client got
+    `missed: 1`, and the client printed a `missed: 3` notice. Branch `remchild` at `e38d7d0`;
+    server running here on 8799 with `--allow-all` and the static client rebuilt for scp.
   - [x] C80 Request Desktop Website is honored. The layout was already width-driven, so browsers
     that widen the viewport for desktop mode (Safari, Chrome) got the desktop layout. Browsers
     that only swap the user agent (Firefox Android) stayed mobile. `app.js` now detects that case