Add activate command to quickstart (#366)

Update create-a-toolkit.mdx

Author: sdreyer

pages/home/build-tools/create-a-toolkit.mdx

@@ -93,6 +93,18 @@ The Makefile provides several helpful commands:
 - `install-local` - Install Arcade components (CLI, TDK, etc.) from source in editable mode. Only use this when you are developing against the latest unreleased code from the [arcade-ai repo](https://github.com/ArcadeAI/arcade-ai) main branch instead of the published packages
 - `test` - Test the code with pytest
 
+
+Activate the environment with:
+```bash
+source .venv/bin/activate
+```
+
+or
+
+```bash
+uv run
+```
+
 ## Define your tools
 
 Create a Python file for your tools in the `arcade_arithmetic/tools` directory.