build(deps): bump the pip group across 2 directories with 1 update

Bumps the pip group with 1 update in the / directory: [langchain](https://github.com/langchain-ai/langchain).
Bumps the pip group with 1 update in the /backend directory: [langchain](https://github.com/langchain-ai/langchain).


Updates `langchain` from 0.2.15 to 0.3.0
- [Release notes](https://github.com/langchain-ai/langchain/releases)
- [Commits](https://github.com/langchain-ai/langchain/compare/langchain==0.2.15...langchain==0.3.0)

Updates `langchain` from 0.2.15 to 0.3.0
- [Release notes](https://github.com/langchain-ai/langchain/releases)
- [Commits](https://github.com/langchain-ai/langchain/compare/langchain==0.2.15...langchain==0.3.0)

---
updated-dependencies:
- dependency-name: langchain
  dependency-type: direct:production
  dependency-group: pip
- dependency-name: langchain
  dependency-type: direct:production
  dependency-group: pip
...

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

backend/requirements.txt

@@ -35,7 +35,7 @@ anthropic
 google-generativeai==0.7.2
 tiktoken
 
-langchain==0.2.15
+langchain==0.3.0
 langchain-community==0.2.12
 langchain-chroma==0.1.4
 

pyproject.toml

@@ -42,7 +42,7 @@ dependencies = [
     "google-generativeai==0.7.2",
     "tiktoken",
 
-    "langchain==0.2.15",
+    "langchain==0.3.0",
     "langchain-community==0.2.12",
     "langchain-chroma==0.1.4",