Update documentation to v1.1.20 with current features

- Updated all version references to 1.1.20
- Updated WordPress requirement to 6.0+ (tested up to 6.9.x)
- Updated WooCommerce requirement to 8.0+ (tested up to 10.x)
- Added comprehensive file structure showing Twig templates
- Added WooCommerce Blocks compatibility documentation
- Added tier labels feature documentation (v1.1.7)
- Added quantity restrictions feature documentation (v1.1.0)
- Added new usage examples for tier labels and quantity restrictions
- Updated INSTALLATION.md with complete directory structure
- Updated README.md with current version changelog
- Updated QUICKSTART.md with 8 pro tips including new features
- Updated USAGE_EXAMPLES.md with 6 complete examples
- Documented WooCommerce Blocks support and v1.1.20 critical fix

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

QUICKSTART.md

@@ -1,6 +1,6 @@
 # Quick Start Guide
 
-Get started with WooCommerce Tier and Package Prices in 5 minutes!
+Get started with WooCommerce Tier and Package Prices (v1.1.20) in 5 minutes!
 
 ## Step 1: Install (2 minutes)
 
@@ -79,8 +79,11 @@ Use packages for common bundles (6-pack, dozen, case)
 1. **Round Numbers**: Use 10, 25, 50, 100 for tiers
 2. **Meaningful Savings**: Offer at least 10% off per tier
 3. **Label Packages**: "Family Pack" sells better than "4-pack"
-4. **Test Checkout**: Always complete a test order
-5. **Mobile Check**: View on phone to verify responsiveness
+4. **Label Tiers**: Use descriptive labels like "Wholesale Price" or "Bulk Discount"
+5. **Test Checkout**: Always complete a test order
+6. **Mobile Check**: View on phone to verify responsiveness
+7. **Quantity Restrictions**: Enable package restrictions to prevent arbitrary quantities
+8. **Blocks Compatible**: Works with both classic and block-based carts/checkout
 
 ## Need More Help?