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.

package.json

@@ -3,6 +3,8 @@
   "version": "0.1.0",
   "private": true,
   "scripts": {
+    "predev": "tsx scripts/init-db.ts",
+    "prebuild": "tsx scripts/init-db.ts",
     "dev": "next dev",
     "build": "next build",
     "start": "next start",
@@ -10,6 +12,7 @@
     "format": "biome format --write"
   },
   "dependencies": {
+    "better-sqlite3": "^12.4.1",
     "class-variance-authority": "^0.7.1",
     "clsx": "^2.1.1",
     "lucide-react": "^0.548.0",
@@ -29,10 +32,12 @@
   "devDependencies": {
     "@biomejs/biome": "2.2.0",
     "@tailwindcss/postcss": "^4",
+    "@types/better-sqlite3": "^7.6.13",
     "@types/node": "^20",
     "@types/react": "^19",
     "@types/react-dom": "^19",
     "tailwindcss": "^4",
+    "tsx": "^4.20.6",
     "typescript": "^5"
   }
 }