add a profile photo for chatbot, styling fixes, add button to reset session, load an epub instead of our github vector embeddings

src/lib/store.ts

@@ -1,5 +1,26 @@
 import { writable } from 'svelte/store';
 import type { SearchResult } from './utils/search';
+import type { HumanMessage, AIMessage, SystemMessage } from '@langchain/core/messages';
 
 const initArray: SearchResult[] = [];
 export const searchResults = writable(initArray);
+
+export type ChatHistory = (HumanMessage | AIMessage | SystemMessage)[];
+
+const chatHistories: Record<string, ChatHistory> = {};
+
+export const chatStore = writable(chatHistories);
+
+export function getChatHistory(sessionId: string): ChatHistory {
+	return chatHistories[sessionId] || [];
+}
+
+export function setChatHistory(sessionId: string, history: ChatHistory): void {
+	chatHistories[sessionId] = history;
+	chatStore.set(chatHistories);
+}
+
+export function clearChatHistory(sessionId: string): void {
+	chatHistories[sessionId] = [];
+	chatStore.set(chatHistories);
+}