lib/templates/: registry + one module per template, localized via t()
at build time. applyTemplate (App.svelte) reuses the extracted
resetDocumentState() from handleNew, then assigns the template's
margins, styles and fold marks; no file handle, so Save asks where.
Gallery dialog reachable from the ribbon File menu and the modern
chrome; first template is a DIN 5008 Form B business letter built from
placeholder fields, with the address field at 45mm and a 10cm info tab.
