feat: enhance image generation form with direct generation and improved UX

[RafiulM]

Summary

• ✅ Convert form to generate images directly on the landing page instead of navigating to separate sessions
• ✅ Add comprehensive React state management with useState hooks for prompt text, loading state, error messages, and generated image URL
• ✅ Implement conditional rendering for different UI states: idle, loading, success, and error
• ✅ Add prompt history functionality using localStorage that stores the last 10 unique prompts
• ✅ Implement comprehensive accessibility improvements including ARIA labels, screen reader announcements, and keyboard navigation
• ✅ Add retry functionality for failed generations with clear error messaging
• ✅ Ensure WCAG 2.1 AA compliance with proper roles, live regions, and focus management
• ✅ Improve visual feedback with loading spinners, progress messages, and proper button states
• ✅ Add "Generate Another Image" functionality for seamless user workflow

Test plan

• Test form submission with valid prompts - should generate image directly on page
• Test loading state - should show spinner and progress message
• Test successful generation - should display generated image with proper alt text
• Test error handling - should show error message with retry button
• Test prompt history - should store and display previous prompts in dropdown
• Test accessibility with screen reader - all interactive elements should have proper labels
• Test keyboard navigation - should be able to navigate and interact with all elements
• Test "Generate Another Image" button - should clear result and reset form
• Test responsive design across different screen sizes
• Test form validation - empty prompts should be rejected

🤖 Generated with Claude Code