feat: inject PAPERLESS_URL environment variable and update document link rendering in MailDetailPage

paperless-frontend/docker-entrypoint.sh

@@ -7,6 +7,7 @@ ENV_JS="/usr/share/nginx/html/env-config.js"
 cat <<EOF > "$ENV_JS"
 window.__ENV__ = {
   VITE_API_URL: "${VITE_API_URL:-}",
+  PAPERLESS_URL: "${PAPERLESS_URL:-}",
   VITE_OIDC_AUTHORITY: "${VITE_OIDC_AUTHORITY:-}",
   VITE_OIDC_CLIENT_ID: "${VITE_OIDC_CLIENT_ID:-}",
   VITE_OIDC_REDIRECT_URI: "${VITE_OIDC_REDIRECT_URI:-}",