Professional report engine

Added

• Report builder: compose a document from a selection, choose which blocks to print, and save the layout to reuse it from one report to the next.
• Catalogue table of contents and indexes computed at generation time: page numbers follow the actual content, with no manual pass after adding a work.
• PDF/A export for long-term archiving — the format institutions accept for deposit.
• Verification QR codes printed on generated documents, so a reader can find the source record without retyping a reference.

Improved

• Reports are now written as they are generated rather than assembled in memory: a catalogue of several thousand entries exports without exhausting the machine, and progress stays readable throughout.

Fixed

• QR code generation made reliable when several documents are produced in parallel.