feat: comprehensive improvements to GitHub Pages documentation site

Major enhancements to improve user experience and visual design:

**Visual & Design Improvements:**
- Fix skip-to-content link positioning - now centred and properly visible on focus
- Add Fira Sans font family for modern, coding-focused typography
- Enhance hero section with dark gradient background and grid pattern
- Improve overall contrast with darker, more professional colour scheme
- Increase hero title size and prominence with better letter spacing
- Add text shadows and visual depth to key elements

**New Content Sections:**
- Add "Real-World Use Cases" section with 6 practical examples:
  * Personal portfolio websites
  * AI-powered SaaS applications
  * Analytics dashboards
  * E-commerce platforms
  * API backend services
  * Chat applications
- Add "Traditional Workflow vs This Template" comparison showing 5-8 days saved
- Visualise workflow steps with time estimates for both approaches
- Highlight time savings with prominent call-out section

**Claude Code PRP Feature Spotlight:**
- Create dedicated spotlight section for /generate-prp command
- Explain benefits of Product Requirement Plans:
  * Clarifying requirements before coding
  * Planning architecture systematically
  * Executing with precision
- Add visual workflow showing 5-step PRP process
- Highlight /generate-prp and /execute-prp commands with badges
- Add "Featured Command" badge and detailed explanation

**Technical Improvements:**
- Import Fira Sans and Fira Mono fonts from Google Fonts
- Add CSS custom properties for new colour schemes
- Create responsive styles for all new sections
- Add animation support for new elements (fade-in on scroll)
- Improve mobile responsiveness with better breakpoints
- Add new CSS classes for use cases, workflows, and PRP sections

**Accessibility:**
- Fix skip link to be keyboard accessible and properly positioned
- Maintain ARIA labels and semantic HTML throughout
- Ensure sufficient colour contrast ratios
- Add proper focus states for all interactive elements

These improvements make the site more beginner-friendly by clearly
explaining use cases, showing concrete examples, and demonstrating
the value proposition through workflow comparisons.

Author: claude