Build a Progress Bar component in React that shows the percentage completion of an operation.
Requirements:
- Render a progress bar that visually represents completion percentage.
- Allow updating the percentage using a number input or button.
- The bar should fill proportionally to the percentage (0–100).
- Display the percentage as text inside or above the bar.
- Focus on functionality over styling.
- The component should work out-of-the-box in a live React preview (e.g., CodeSandbox/Sandpack).