feat: add Brave Search integration (#4)

* feat: add Brave Search integration

- Add Brave Search implementation
- Configure Brave API key in config
- Make search provider configurable with Brave as default

Co-Authored-By: Han Xiao <han.xiao@jina.ai>

* chore: first commit

---------

Co-authored-by: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>
Co-authored-by: Han Xiao <han.xiao@jina.ai>

package.json

@@ -16,8 +16,11 @@
   "description": "",
   "dependencies": {
     "@google/generative-ai": "^0.21.0",
+    "@types/node-fetch": "^2.6.12",
+    "axios": "^1.7.9",
     "dotenv": "^16.4.7",
     "duck-duck-scrape": "^2.2.7",
+    "node-fetch": "^3.3.2",
     "undici": "^7.3.0"
   },
   "devDependencies": {