TicketBAI maintains independent chains per invoice series (INV, RINV, etc).
When building the chain for a new invoice, ensure it links to the previous
valid document from the same series, not just the last document regardless
of series.
Fixes error "time data '' does not match format '%d-%m-%Y'" when previous
document's XML is missing or when wrong series document is used for chaining.
- Override _get_sale_values to validate series match
- Add _get_last_chained_document_by_series to filter by series+state+xml
- Skip cancelled documents and documents without valid XML
Co-Authored-By: Claude Haiku 4.5 <noreply@anthropic.com>
