update dev container

Author: Chenglong-MS

.devcontainer/devcontainer.json

@@ -17,7 +17,7 @@
 	// "forwardPorts": [],
 
 	// Use 'postCreateCommand' to run commands after the container is created.
-	"postCreateCommand": "python3 -m venv /workspaces/data-formulator/venv && . /workspaces/data-formulator/venv/bin/activate && pip install https://github.com/user-attachments/files/17319752/data_formulator-0.1.0.tar.gz --verbose && data_formulator"
+	"postCreateCommand": "cd /workspaces/data-formulator && npm install && npm run build && python3 -m venv /workspaces/data-formulator/venv && . /workspaces/data-formulator/venv/bin/activate && pip install -e /workspaces/data-formulator --verbose && data_formulator"
 
 	// Configure tool-specific properties.
 	// "customizations": {},