Stable version with new spinner types

Added new spinners

New Feature: Dot Shape Customization

Added `shape` prop to render dots as SVG circles, squares, or diamonds:
- New `DotShape` type exported from public API
- Added `brailleToGrid()` utility for decoding braille frames
- Implemented `SpinnerShapeSVG` component for SVG rendering
- Added `defaultShape` to SpinnerProvider for global configuration
- Demo updated with shape selector, reset button, and optimized layout

Usage:
  <Spinner name="helix" shape="square" color="#00ff99" />
  <SpinnerProvider defaultShape="diamond">

Backward compatible - shape defaults to undefined (braille text).

README LLM/GEO Optimization

Improved AI citation readiness:
- Enhanced tagline and features list
- Competitive positioning vs other spinner libraries
- Added FAQ and common patterns sections
- Better E-E-A-T signals for LLM discovery

Co-Authored-By: Claude Haiku 4.5 <noreply@anthropic.com>