fix(chat): reset chat state on identifier change via key prop

Keying `<ChatClient>` on `identifier` guarantees a full remount on
route transitions between chats, so `conversationId`, `messages`, and
every other piece of local state start fresh — no reset effect
required.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

Author: waleedlatif1

apps/sim/app/chat/[identifier]/page.tsx

@@ -7,5 +7,5 @@ export const metadata: Metadata = {
 
 export default async function ChatPage({ params }: { params: Promise<{ identifier: string }> }) {
   const { identifier } = await params
-  return <ChatClient identifier={identifier} />
+  return <ChatClient key={identifier} identifier={identifier} />
 }