Slice 2 wave 3: wire chat end-to-end at the composition root

- app/store.svelte.ts: one WebSocket carries surfaces AND chat (onChat ->
  chatStore.handleDelta); build the conversation cache over the IndexedDB
  adapter; createChatStore wired to transport (socket.send), injected HTTP
  historySync, and the cache; load() on construct
- app/resolve-http-url.ts: host-relative HTTP base (port 24203), mirrors
  resolve-ws-url; injected fetch
- App.svelte: render ChatView + Composer alongside the surface picker
- createAppStore gains optional injection points (httpUrl/fetchImpl/indexedDB/
  conversationId) for tests
- vitest-setup.ts: fake-indexeddb/auto for jsdom IndexedDB (orchestrator-owned
  config; agent change adopted)

Verified green (x2, stable): svelte-check 0/0, vitest 218, biome clean, build ok.
Slice 2 (conversation transcript: cache + delta streaming) feature-complete.

1 files changed, 18 insertions, 0 deletions

diff --git a/src/app/App.svelte b/src/app/App.svelte
index 2619a39..92939c2 100644
--- a/src/app/App.svelte
+++ b/src/app/App.svelte
@@ -1,6 +1,7 @@
 <script lang="ts">
 	import type { InvokeMessage } from "@dispatch/ui-contract";
 	import { SurfaceView } from "../features/surface-host";
+	import { ChatView, Composer } from "../features/chat";
 	import type { AppStore } from "./store.svelte";
 
 	let { store }: { store: AppStore } = $props();
@@ -12,6 +13,10 @@
 	function handleInvoke(msg: InvokeMessage) {
 		store.invoke(msg.surfaceId, msg.actionId, msg.payload);
 	}
+
+	function handleSend(text: string) {
+		store.chat.send(text);
+	}
 </script>
 
 <main>
@@ -24,6 +29,19 @@
 		</div>
 	{/if}
 
+	{#if store.chat.error}
+		<div role="alert">
+			<strong>Chat error:</strong>
+			{store.chat.error}
+		</div>
+	{/if}
+
+	<section>
+		<h2>Chat</h2>
+		<ChatView chunks={store.chat.chunks} />
+		<Composer onSend={handleSend} />
+	</section>
+
 	<section>
 		<h2>Surfaces</h2>
 		{#if store.catalog.length === 0}