fix: Update contributing and fix logo

CONTRIBUTING.md

@@ -15,6 +15,7 @@ I've copy/pasted the whole document there, and then formatted it with prettier.
     - [Requirements](#requirements)
     - [Set up the repo](#set-up-the-repo)
     - [Install dependencies](#install-dependencies)
+    - [Build Frontend](#build-frontend)
   - [Start the Chainlit server from source](#start-the-chainlit-server-from-source)
   - [Start the UI from source](#start-the-ui-from-source)
   - [Run the tests](#run-the-tests)
@@ -78,6 +79,14 @@ cd backend
 uv sync --extra tests --extra mypy --extra dev --extra custom-data
 ```
 
+### Build Frontend
+
+The following will build the frontend distributions locally. From the root of the repo:
+
+```sh
+pnpm run buildUi
+```
+
 ## Start the Chainlit server from source
 
 Start by running `backend/hello.py` as an example.