chore(web): add caddy compression and re-export MuJoCo presets at 60Hz

Caddyfile

@@ -0,0 +1,5 @@
+:8676 {
+  root * .
+  file_server
+  encode zstd gzip
+}

README.md

@@ -46,7 +46,15 @@ Any static server is enough.
 
 No build step is required. Three.js is loaded via ESM URL imports.
 
-Example with Python:
+Recommended (compressed static serving for large MuJoCo JSON presets):
+
+```bash
+caddy run
+```
+
+This uses the repo `Caddyfile` (`zstd` + `gzip`) on `http://localhost:8676`.
+
+If you do not have Caddy installed, a basic uncompressed fallback is:
 
 ```bash
 python3 -m http.server 8676