chore: integrate firestore for particles (#32)

* plumb for firestore

* chore: cleanup orion api to only include essentials

* setup boilerplate for data and rendering

This includes zod types creation for API response validation, and
exploration of path based resolution of rendering particles.

* chore: structure container particles for rendering children

* wire firestore crud for particles

* integrate visibility to particles

* docs: explain particle view resolver

js/src/features/particles/particle-list-view.tsx

@@ -0,0 +1,43 @@
+import { useParticleChildren } from "@/hooks/use-particle-children";
+
+interface ParticleListViewProps {
+  networkId: string;
+  particleSegments: string[];
+}
+
+/**
+ * Grid/list of child particles for a container (folder, stream root, or network root).
+ */
+export function ParticleListView({ networkId, particleSegments }: ParticleListViewProps) {
+  const { children, isLoading } = useParticleChildren(networkId, particleSegments);
+
+  if (isLoading) {
+    return (
+      <div className="flex h-full items-center justify-center">
+        <p className="text-muted-foreground text-sm">Loading particles...</p>
+      </div>
+    );
+  }
+
+  if (children.length === 0) {
+    return (
+      <div className="flex h-full items-center justify-center">
+        <p className="text-muted-foreground text-sm">No particles yet</p>
+      </div>
+    );
+  }
+
+  return (
+    <div className="grid grid-cols-2 gap-3 p-4">
+      {children.map((child) => (
+        <div
+          key={child.id}
+          className="rounded-lg border p-3 text-sm"
+        >
+          <p className="font-medium">{child.id}</p>
+          <p className="text-muted-foreground text-xs">{child.type}</p>
+        </div>
+      ))}
+    </div>
+  );
+}