feat(backend): who of the given people is online now in one request

backend/src/api/routers/presence.py

@@ -9,6 +9,7 @@ from api.timezone import checked_tz
 from utils.read import presence, presence_stats
 from utils.read.models import (
     DEFAULT_LIMIT,
+    MAX_LIMIT,
     Page,
     PresenceHourly,
     PresenceSample,
@@ -54,6 +55,16 @@ async def current_presence(
     return await presence.current_presence(pool, account_id, peer_id)
 
 
+@router.get("/online")
+async def online_now(
+    pool: FromDishka[asyncpg.Pool],
+    account_id: AccountId,
+    peer_ids: Annotated[str, Query()],
+) -> list[PresenceSample]:
+    parsed = [int(part) for part in peer_ids.split(",") if part.strip()]
+    return await presence.online_now(pool, account_id, parsed[:MAX_LIMIT])
+
+
 @router.get("/hourly")
 async def presence_hourly(
     pool: FromDishka[asyncpg.Pool],