Replace the cartoon-style OG image with a clean, text-based design
inspired by VocaMac's approach:
- Left side: Logo, tagline, feature bullets, GitHub CTA, distro pills
- Right side: Feature cards with SVG icons and colored badges
- Proper SVG vector icons (shield, keyboard, lightning, microphone)
- Brand gradient accent lines top and bottom
- Added SVG source file for future edits
Image size reduced from 1.1MB to 113KB (PNG) and 96KB to 41KB (webp).
