Basis: Certvia dev@a48c5fb als Fundament für Craftvia

Unveränderter Stand von certvia/dev (a48c5fb) plus Craftvia-Spezifikation
und Brandbook unter docs/craftvia/. ISMS-Module werden im Folgecommit entfernt.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

public/assets/logo/certvia-mark-grau.svg

@@ -0,0 +1,4 @@
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 64 64" width="256" height="256" role="img" aria-label="Certvia">
+  <path d="M46 20 A17 17 0 1 0 46 44" fill="none" stroke="#8a8a90" stroke-width="6" stroke-linecap="round"/>
+  <path d="M27 32 l6 6 l12 -15" fill="none" stroke="#8a8a90" stroke-width="5" stroke-linecap="round" stroke-linejoin="round"/>
+</svg>