chat: delete dead EmailChat.tsx

Orphaned standalone email-assistant chat, superseded by the officerdev/chat panel
(ChatPanelWrapper) that the email layout uses. Imported nowhere.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/apps/officer-web/Screens/Dashboard/Email/EmailChat.tsx

@@ -1,17 +0,0 @@
-import { EmbeddableChat, usePiChat } from 'officerdev';
-
-const PROMPT_PREFIX = `You are an email assistant. The user has a local SQLite email database available via the "email_db" tool — use it for all email queries (search, count, stats, aggregations, deletions) unless the user explicitly asks you to use Gmail. Do not use the Gmail integration for questions about existing emails.`;
-
-export const EmailChat = () => {
-  const chat = usePiChat(undefined, undefined, { replaceUrl: false });
-
-  return (
-    <EmbeddableChat
-      className="h-full"
-      chat={chat}
-      sandboxed
-      replaceUrl={false}
-      promptPrefix={PROMPT_PREFIX}
-    />
-  );
-};