feat: Add .venv to .gitignore and improve script error handling

Adds the `.venv` directory to the `.gitignore` file to prevent accidental commits.

Also, enhances the `scripts/setup-python.sh` script to include error handling for the `pip install` command, providing a more informative message if the upgrade fails.

.gitignore

@@ -66,4 +66,6 @@ temp/
 
 exports/*
 
-.agent-builder-sessions/*
+.agent-builder-sessions/*
+
+.venv

scripts/setup-python.sh

@@ -72,7 +72,10 @@ echo ""
 
 # Upgrade pip, setuptools, and wheel
 echo "Upgrading pip, setuptools, and wheel..."
-$PYTHON_CMD -m pip install --upgrade pip setuptools wheel > /dev/null 2>&1
+if ! $PYTHON_CMD -m pip install --upgrade pip setuptools wheel; then
+  echo "Error: Failed to upgrade pip. Please check your python/venv configuration."
+  exit 1
+fi
 echo -e "${GREEN}✓${NC} Core packages upgraded"
 echo ""