chore(deps): bump google-genai from 2.15.0 to 2.16.0

Bumps [google-genai](https://github.com/googleapis/python-genai) from 2.15.0 to 2.16.0.
- [Release notes](https://github.com/googleapis/python-genai/releases)
- [Changelog](https://github.com/googleapis/python-genai/blob/main/CHANGELOG.md)
- [Commits](googleapis/python-genai@v2.15.0...v2.16.0)

---
updated-dependencies:
- dependency-name: google-genai
  dependency-version: 2.16.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

pyproject.toml

@@ -22,7 +22,7 @@ dependencies = [
   "anthropic==0.120.2",
   "keyring==25.7.0",
   "groq==1.6.0",
-  "google-genai==2.15.0",
+  "google-genai==2.16.0",
   "httpx[socks]==0.28.1",
   "boto3==1.43.59",
   "aws-bedrock-token-generator==1.1.0"