feat(cert-manager): cert role badges + ZIP download in split view

- API: detectCertRole() classifies certs as root/intermediate/end-entity
  via basicConstraints.cA + self-signed check (subject.hash === issuer.hash)
- API: SplitEntry gains certRole field; filenames now reflect role
  (root-ca.pem, intermediate-1.pem, cert.pem)
- Web: SplitTab shows colour-coded role badge per cert
  (red=Root-CA, amber=Zwischen-CA, blue=Zertifikat)
- Web: "Alle als ZIP herunterladen" button via fflate (client-side)
- i18n: add certRole labels + downloadZip action key (de + en)
- i18n: add missing accentColor* and deleteAvatar* keys (de + en)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

apps/web/package.json

@@ -11,6 +11,7 @@
   },
   "dependencies": {
     "@uiw/react-md-editor": "4.1.1",
+    "fflate": "^0.8.3",
     "jose": "^6.2.3",
     "next": "^15.3.0",
     "next-intl": "^4.13.0",