feat: filter to ephemeral streams and particles

js/src/lib/constants.ts

@@ -0,0 +1,2 @@
+/** How far back to look when filtering particles by recency. */
+export const RECENCY_WINDOW_HOURS = 24;

js/src/lib/firestore-particles.ts

@@ -16,6 +16,7 @@ import {
   type QueryDocumentSnapshot,
   type SnapshotOptions,
   type Unsubscribe,
+  QueryFieldFilterConstraint,
 } from "firebase/firestore";
 import { firestoreDb } from "@/firebase";
 import { isContainerType, ParticleSchema } from "@/api/types";
@@ -134,6 +135,7 @@ export function subscribeToParticleChildren(
   orderDirection: "asc" | "desc" = "desc",
   onAdded?: (child: Particle) => void,
   onRemoved?: (child: Particle, updatedChildren: Particle[]) => void,
+  whereFilter?: QueryFieldFilterConstraint,
 ): Unsubscribe {
   let q = query(typedCollection(collectionPath), orderBy(orderByField, orderDirection));
   if (visibilityScopes.length > 0) {
@@ -142,6 +144,9 @@ export function subscribeToParticleChildren(
       where("visible_to", "array-contains-any", visibilityScopes),
     );
   }
+  if (whereFilter) {
+    q = query(q, whereFilter);
+  }
   return onSnapshot(
     q,
     (snap) => {