Consolidate and migrate custom uploader UI implementations to use standardized components from @storacha/ui-react.

Background

The console app's Uploader component already uses core functionality from @storacha/ui-react (W3Uploader, WrapInDirectoryCheckbox, useUploader) but has extensive custom UI implementations for status displays, progress tracking, and result handling.

Tasks

• Evaluate if custom UI components can be generalized for @storacha/ui-react
• Create standardized progress display components in @storacha/ui-react
• Migrate error handling UI to shared library
• Standardize upload completion UI patterns
• Extract encryption-specific logic for potential separate module
• Implement privacy mode toggle as a reusable component
• Update styling to use consistent design tokens
• Ensure accessibility standards are met (ARIA labels, keyboard navigation)