Add presence indicators and a manual "appear offline" override (#36)

Every avatar in the app (chat messages, room member list, your own
avatar in the top bar/profile, the admin user list, the room-invite
search) now shows a green/red presence dot. Also adds a global
"Appear offline" toggle in the account menu, letting a user lurk in a
room undetected -- it overrides the real connection state everywhere,
not per-room.

Backend: new GlobalPresence (backend/app/ws/global_presence.py), a
cross-instance Redis-backed connection tracker parallel to the
existing per-room Presence, incremented/decremented on WS connect/
disconnect. A new users.appear_offline column (migration
f0f6e494454a) always wins over actual connection state when computing
displayed status. RoomMemberRead gained a computed `status` field;
add_member/change_member_role/list_room_members all compute it via a
shared _member_status() helper. Connect/disconnect and profile
updates (display_name, avatar, appear_offline) all broadcast
member_updated to every room the user belongs to, reusing the
broadcast infrastructure from the earlier avatar-staleness fix, so
chat surfaces update live with no new WS envelope type needed. A new
GET /api/users/online gives the admin list and user-search a snapshot
(deliberately not live -- see backend/app/routers/users.py) for
surfaces where "accurate as of page load" is good enough.

Frontend: UserAvatar renders an optional status dot; every call site
threads status/appear_offline through from whichever data source it
already has (room members, the current user, or the new online-ids
snapshot for admin/search).

4 new backend tests (backend/tests/test_presence.py); existing
broadcast-adjacent WS tests updated to tolerate the new member_updated
noise on connect. Verified end-to-end in the browser with two real
users: presence dot flips live on connect/disconnect via the existing
room-broadcast channel, and the lurk toggle correctly forces offline
while still connected.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

backend/app/routers/auth.py

@@ -85,11 +85,13 @@ async def update_profile(
         current_user.display_name = display_name or None
     if "theme" in updates:
         current_user.theme = updates["theme"]
+    if "appear_offline" in updates:
+        current_user.appear_offline = updates["appear_offline"]
     await db.commit()
     await db.refresh(current_user)
     # theme is private to this user, not shown to anyone else -- only
     # broadcast when something other members would actually see changed.
-    if "display_name" in updates:
+    if "display_name" in updates or "appear_offline" in updates:
         await broadcast_member_updated(db, request.app.state.broadcaster, current_user.id)
     return current_user
 

backend/app/routers/rooms.py

@@ -201,14 +201,24 @@ async def leave_room_endpoint(
         raise HTTPException(status_code=404, detail="Not a member of this room")
 
 
+def _member_status(user: User, online_ids: set[uuid.UUID]) -> str:
+    # appear_offline always wins, regardless of actual connection -- that's
+    # the whole point of the override (lurking in a room undetected).
+    return "offline" if user.appear_offline or user.id not in online_ids else "online"
+
+
 @router.get("/{room_id}/members", response_model=list[RoomMemberRead])
 async def list_room_members_endpoint(
+    request: Request,
     room_id: uuid.UUID,
     current_user: User = Depends(get_current_user),
     db: AsyncSession = Depends(get_db),
 ):
     await require_room_member(room_id, current_user, db)
     memberships = await list_room_members(db, room_id)
+    online_ids = await request.app.state.global_presence.online_user_ids(
+        [m.user_id for m in memberships]
+    )
     return [
         RoomMemberRead(
             user_id=m.user_id,
@@ -217,6 +227,7 @@ async def list_room_members_endpoint(
             avatar_filename=m.user.avatar_filename,
             role=m.role,
             joined_at=m.joined_at,
+            status=_member_status(m.user, online_ids),
         )
         for m in memberships
     ]
@@ -244,6 +255,7 @@ async def remove_member_endpoint(
 
 @router.patch("/{room_id}/members/{user_id}", response_model=RoomMemberRead)
 async def change_member_role_endpoint(
+    request: Request,
     room_id: uuid.UUID,
     user_id: uuid.UUID,
     data: RoomMemberRoleUpdate,
@@ -259,6 +271,7 @@ async def change_member_role_endpoint(
         raise HTTPException(
             status_code=400, detail="Use transfer-ownership to change the room owner"
         )
+    online_ids = await request.app.state.global_presence.online_user_ids([membership.user_id])
     return RoomMemberRead(
         user_id=membership.user_id,
         username=membership.user.username,
@@ -266,6 +279,7 @@ async def change_member_role_endpoint(
         avatar_filename=membership.user.avatar_filename,
         role=membership.role,
         joined_at=membership.joined_at,
+        status=_member_status(membership.user, online_ids),
     )
 
 
@@ -468,6 +482,7 @@ async def add_member_endpoint(
     except AlreadyMemberError:
         raise HTTPException(status_code=409, detail="That user is already a member")
     await broadcast_room_added(request.app.state.broadcaster, data.user_id, room)
+    online_ids = await request.app.state.global_presence.online_user_ids([membership.user_id])
     return RoomMemberRead(
         user_id=membership.user_id,
         username=membership.user.username,
@@ -475,6 +490,7 @@ async def add_member_endpoint(
         avatar_filename=membership.user.avatar_filename,
         role=membership.role,
         joined_at=membership.joined_at,
+        status=_member_status(membership.user, online_ids),
     )
 
 

backend/app/routers/users.py

@@ -1,6 +1,6 @@
 import uuid
 
-from fastapi import APIRouter, Depends, HTTPException
+from fastapi import APIRouter, Depends, HTTPException, Request
 from fastapi.responses import FileResponse
 from sqlalchemy import select
 from sqlalchemy.ext.asyncio import AsyncSession
@@ -27,6 +27,25 @@ async def list_users_directory_endpoint(
     return list(result.scalars().all())
 
 
+@router.get("/online", response_model=list[uuid.UUID])
+async def list_online_users_endpoint(
+    request: Request,
+    current_user: User = Depends(get_current_user),
+    db: AsyncSession = Depends(get_db),
+) -> list[uuid.UUID]:
+    """A snapshot, not a live feed -- deliberately simpler than the presence
+    dot in chat (which updates live via the existing room-broadcast
+    machinery). Used by surfaces where "accurate as of page load" is good
+    enough: the admin user list and the room-invite user search."""
+    raw_online_ids = await request.app.state.global_presence.all_online_user_ids()
+    if not raw_online_ids:
+        return []
+    result = await db.execute(
+        select(User.id).where(User.id.in_(raw_online_ids), User.appear_offline.is_(False))
+    )
+    return [row[0] for row in result.all()]
+
+
 @router.get("/{user_id}/avatar")
 async def get_user_avatar_endpoint(
     user_id: uuid.UUID,