feat: add database support, conversation sidebar, and improve chat streaming

- Update .gitignore to exclude database files, extensions, and .cursor directory
- Enhance chat streaming API with safe enqueue and close functions to prevent errors
- Integrate ConversationSidebar component into ClientHome for better UI
- Add dependencies like better-sqlite3 and esbuild packages for database functionality

This commit introduces database persistence for conversations, improves error handling in streaming responses, and adds a sidebar for managing chats, enhancing overall app robustness and user experience.

database/client.ts

@@ -0,0 +1,34 @@
+import Database from "better-sqlite3";
+import path from "path";
+import fs from "fs";
+
+let db: Database.Database | null = null;
+
+export function getDatabase(): Database.Database {
+  if (!db) {
+    const dbPath = path.join(process.cwd(), "database", "ollahub.db");
+
+    // Garantir que o diretório existe
+    const dbDir = path.dirname(dbPath);
+    if (!fs.existsSync(dbDir)) {
+      fs.mkdirSync(dbDir, { recursive: true });
+    }
+
+    db = new Database(dbPath);
+
+    // Configurações de performance
+    db.pragma("journal_mode = WAL");
+    db.pragma("synchronous = NORMAL");
+    db.pragma("foreign_keys = ON");
+    db.pragma("cache_size = 10000");
+    db.pragma("temp_store = memory");
+  }
+  return db;
+}
+
+export function closeDatabase(): void {
+  if (db) {
+    db.close();
+    db = null;
+  }
+}