fix(build): add venv activation to commands and improve error handling

justfile

@@ -4,15 +4,19 @@ default:
 
 # Create and activate virtual environment
 venv:
-    python -m venv venv
-    @echo "Virtual environment created. Activate it with 'source venv/bin/activate' (Unix) or 'venv\\Scripts\\activate' (Windows)"
+    python3 -m venv venv || (echo "Error: Failed to create virtual environment. Make sure python3 and python3-venv are installed." && exit 1)
+    echo "Virtual environment created. Activate it with 'source venv/bin/activate' (Unix) or 'venv\\Scripts\\activate' (Windows)"
 
 # Install required packages (run after activating venv)
 install:
+    #!/usr/bin/env bash
+    source venv/bin/activate
     pip install -r requirements.txt
 
 # Run the Streamlit application
 run:
+    #!/usr/bin/env bash
+    source venv/bin/activate
     streamlit run scrape_ui.py
 
 # Verify all required files exist
@@ -27,8 +31,10 @@ setup: verify venv install run
 
 # Initialize or reset the database schema
 init-db:
+    #!/usr/bin/env bash
+    source venv/bin/activate
     @echo "Initializing database schema..."
-    @python -c "from scrape_ui import init_db; init_db()"
+    python -c "from scrape_ui import init_db; init_db()"
 
 # Clean the database (removes all stored URLs)
 clean-db: