v1.2.0

v1.2.0: rename BIT-Nova PDF -> BIT-PDF, appId de.bit-atelier.pdf

Trademark: novaPDF (Softland) is an established PDF product, and NOVA AVA
(NOVA Building IT) owns the Nova name family in the construction market.
Product name, artifact names, manifest name/short_name, window title, about
dialog, user agent, README and workflows now say BIT-PDF. manifest.id stays
"novapdf" so installed PWAs keep their identity; repo name and Pages path are
unchanged (stage 2). userData migration list extended so recent.json survives
the productName change. Cache prefix bit-pdf-, VERSION 1.2.0 in all four
places. appId and author no longer reference the operator's employer.

Checks: run-e2e 63/63, check-sw OK (old cache cleared), check-update OK.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>