chore(deps): bump @langchain/core from 1.1.4 to 1.1.8

Bumps [@langchain/core](https://github.com/langchain-ai/langchainjs) from 1.1.4 to 1.1.8.
- [Release notes](https://github.com/langchain-ai/langchainjs/releases)
- [Commits](https://github.com/langchain-ai/langchainjs/compare/@langchain/core@1.1.4...@langchain/core@1.1.8)

---
updated-dependencies:
- dependency-name: "@langchain/core"
  dependency-version: 1.1.8
  dependency-type: direct:production
...

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

Author: dependabot[bot]

packages/ai-proxy/package.json

@@ -15,7 +15,7 @@
     "openai": "4.95.0",
     "@forestadmin/datasource-toolkit": "1.50.1",
     "@langchain/community": "0.3.57",
-    "@langchain/core": "1.1.4",
+    "@langchain/core": "1.1.8",
     "@langchain/langgraph": "1.0.4",
     "@langchain/mcp-adapters": "1.0.3"
   },