docs: new root as prior history lost (orphan + GC); ~215 commits not recoverable

configs/tops/nginx-default.conf

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+# Shared nginx config for tops.ng1–ng3 static previews.
+# Language root redirect mirrors taler-ops.ch (Accept-Language → /en|/de|/fr).
+# Cache: always revalidate / never store — design previews must show latest HTML/assets.
+
+map $http_accept_language $accept_lang {
+    default en;
+    ~*^de de;
+    ~*^fr fr;
+    ~*^en en;
+}
+
+server {
+    listen 80;
+    server_name _;
+    root /usr/share/nginx/html;
+    index index.html;
+
+    # Relative Location: so Caddy/HTTPS clients stay on https://host/...
+    absolute_redirect off;
+    port_in_redirect off;
+    server_name_in_redirect off;
+
+    # Never serve stale preview content from browser/proxy caches
+    etag off;
+    if_modified_since off;
+    expires -1;
+    add_header Cache-Control "no-store, no-cache, must-revalidate, max-age=0, private" always;
+    add_header Pragma "no-cache" always;
+    add_header Expires "0" always;
+
+    # Like https://taler-ops.ch/ — bare root picks language from Accept-Language
+    location = / {
+        return 302 /$accept_lang/;
+    }
+    location = /index.html {
+        return 302 /$accept_lang/;
+    }
+
+    # Bare page names that exist under /{lang}/ (ng2; 302→404 on ng1 if missing)
+    location ~ ^/(merchants|users|users-[a-z]+)\.html$ {
+        return 302 /$accept_lang$uri;
+    }
+
+    location / {
+        try_files $uri $uri/ $uri/index.html =404;
+    }
+}