feat(web): tane.comunes.org landing + localized app screenshots

- Hugo site (site/): EN/ES intro + legal (generated from docs/legal), an
  ES/EN About page from docs/{que-es-tane,what-is-tane}.md, seed-green theme,
  responsive header, store-badge placeholders, multi-stage Hugo->nginx image.
- Golden screenshot harness (test/screenshots/): en,es,fr,de,pt,ja + RTL demo,
  real fonts via DejaVu Sans + FontManifest; skip-by-default tag so CI stays
  green. collect_screenshots.sh feeds site/ and fastlane phoneScreenshots.
- Drop editorial notes from the public explainer.

site/nginx.conf

@@ -0,0 +1,23 @@
+server {
+    listen 80;
+    server_name _;
+    root /usr/share/nginx/html;
+    index index.html;
+
+    # Hugo emits directory-style URLs (/legal/privacy/index.html).
+    location / {
+        try_files $uri $uri/ =404;
+    }
+
+    # Long-cache fingerprinted assets and images; the HTML stays fresh.
+    location ~* \.(png|jpg|jpeg|svg|webp|woff2?|css|js)$ {
+        expires 7d;
+        add_header Cache-Control "public";
+    }
+
+    error_page 404 /404.html;
+
+    gzip on;
+    gzip_types text/css application/javascript image/svg+xml application/xml;
+    gzip_min_length 512;
+}