Rewrites the README to reflect the full current feature set:
- InvoiceReader with auto-detection and InvoiceData structure
- TaxBreakdownData fields and per-parser mapping
- InvoiceRenderer with i18n, custom template/CSS, injected variables
- viewer.php quick-start
- Format support table with generate/read columns

https://claude.ai/code/session_01S1ndnid9CGwh1hAyShLEEh