feat: open community panel (read-only clients only)

Ship full install stack with .amnezia-panel-edition=community; docs and
footer point to Boosty/PRO. Managing peers, export, cascade and WARP
require private PRO build.

Co-authored-by: Cursor <cursoragent@cursor.com>

landing/nginx.conf

@@ -0,0 +1,20 @@
+server {
+    listen 80;
+    server_name _;
+    root /usr/share/nginx/html;
+    index index.html;
+
+    gzip on;
+    gzip_types text/css text/plain application/json application/javascript;
+
+    add_header X-Content-Type-Options nosniff always;
+
+    location / {
+        try_files $uri $uri/ /index.html;
+    }
+
+    location ~* \.css$ {
+        expires 1h;
+        add_header Cache-Control "public, max-age=3600";
+    }
+}