fix(web): link the fork's own source host and drop the upstream star count

The header badge fetched the star count of VocaHQ/vocalinux at build time
and labelled it as Voculinux's. The fetch and the count are gone; the
header, footer and social "source" links now go to the fork repository at
git.bongbetic.com/xavierk/voculinux, as do the issue links, the docs
anchors, the home page JSON-LD and the xbps release card.

Upstream GitHub stays only where it is the real artefact or provenance and
is labelled as such: the install script, the AppImage release card, the
upstream card and the changelog release links. The changelog now says its
entries are upstream history, the open-source page no longer claims
VocaHQ membership or an active GitHub community, and the organization
JSON-LD drops the upstream author as founder. DESIGN.md and PRODUCT.md
follow.

web/DESIGN.md

@@ -136,7 +136,7 @@ Flat fills, 1px borders, paper-window shadows. Small rotations only on decorativ
 - Long URLs wrap (`break-all` / `overflow-wrap`) so mobile never overflows
 
 ### Navigation
-- Sticky paper bar, mark + name, 3–5 text links, GitHub stars on desktop
+- Sticky paper bar, mark + name, 3–5 text links, a "Source" link to the fork repository on desktop (no star count)
 - Mobile menu keeps Install Voculinux as the conversion action
 - Real mobile disclosure with `aria-expanded`
 - Resource-rich footer, not a second mega-menu in the header