Rendering moves into a module Web Worker behind a latest-wins RenderClient
with a watchdog and a handshake-based main-thread fallback. The preview
shows the real PDF through pdf.js at 2x with zoom, page indicator, audit
issues popover and a focus modal. A4/Letter and margin controls are frozen
into each invoice at issue and can be saved as the default (migration M3).
react-pdf and pdf.js are lazy-loaded; the main chunk shrinks from 1.8 MB
to 0.5 MB. The HTML twin and its styles are removed.
Views stay mounted so switching tabs no longer loses a half-typed invoice.
The form autosaves a draft after 1 s, drafts can be resumed or deleted,
and after issuing the form is read-only with Export again, Duplicate and
New invoice actions. A failed export keeps the issued invoice and offers a
retry instead of issuing again. Adds Ctrl+N/S/Enter/L and a shortcut sheet;
F5 and Ctrl+R are blocked in production builds.
xavierk