Face-to-face: peer messages take 15-25 s to appear (poll interval 15 s); target ≤10 s #133

Found in a two-instance UI retest of the social plugin (main e884312; source checked on 649bebe). Follow-up to #124 (closed).

Observed

After the fixes in #124 / #127, a human message from the peer in a face-to-face room still takes about 15-25 s to appear on the other instance.

Expected

Peer messages appear within 10 s (ideally a few seconds while the room is open).

Repro

Two instances in one open face room. Peer sends a message; time until it shows here.

Likely cause (poll interval pinned)

Receiving is pure polling:

• plugins/social/index.js: inboxPollMs: 15_000 is the default for both timers.
• plugins/social/src/social.js: pollFaceRooms runs on a setInterval of config.inboxPollMs (15 s). The inbox poll (same 15 s) can also trigger pollFaceRooms() when it sees a face_room.* event, but it runs on its own unsynchronized timer. Worst case is about 15 s + 15 s; typical 15-25 s matches the observation.

Fix idea: poll open face rooms faster (e.g. 3-5 s) while a room is open and the sidebar/chat is visible, keeping 15 s as the idle rate; keep the as handle cache so this doesn't bring back 404 spam (#122). Make the rate configurable via plugin config.

Product note: usability and simplicity are an explicit owner priority for this plugin: few buttons, short copy, short click paths. Please prefer removing or merging UI over adding more.