feat: autoplay inbound clips

js/src/stores/autoplay-store.ts

@@ -0,0 +1,22 @@
+import { create } from "zustand";
+import type { Particle } from "@/api/types";
+
+type MediaParticle = Extract<Particle, { type: "media" }>;
+
+interface AutoplayState {
+  /** The media particle currently being autoplayed, null when idle */
+  activeParticle: MediaParticle | null;
+  /** The stream this particle belongs to (for click-to-navigate) */
+  streamId: string | null;
+  /** Play a media particle, preempting any currently playing */
+  play: (particle: MediaParticle, streamId: string) => void;
+  /** Stop autoplay and clear state */
+  stop: () => void;
+}
+
+export const useAutoplayStore = create<AutoplayState>((set) => ({
+  activeParticle: null,
+  streamId: null,
+  play: (particle, streamId) => set({ activeParticle: particle, streamId }),
+  stop: () => set({ activeParticle: null, streamId: null }),
+}));