Enable CORS headers for Godot threading support

The game uses threaded WASM (Neon Vortex.side.wasm exists) which
requires Cross-Origin-Embedder-Policy and Cross-Origin-Opener-Policy
headers for SharedArrayBuffer support.

Without these headers, the game only partially loads because the
threading fails to initialize.

Fixes: Partial page loading issue

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

htlm/nginx.conf

@@ -24,12 +24,10 @@ server {
     add_header X-Content-Type-Options "nosniff" always;
     add_header X-XSS-Protection "1; mode=block" always;
 
-    # CORS headers for web workers and WASM
-    # ONLY NEEDED IF GODOT EXPORT USES THREADS MODE
-    # These headers can block input if export is "Regular" (non-threaded)
-    # Commenting out to fix button input issues
-    # add_header Cross-Origin-Embedder-Policy "require-corp" always;
-    # add_header Cross-Origin-Opener-Policy "same-origin" always;
+    # CORS headers for web workers and WASM with threading (side.wasm)
+    # Required for SharedArrayBuffer and threading support
+    add_header Cross-Origin-Embedder-Policy "require-corp" always;
+    add_header Cross-Origin-Opener-Policy "same-origin" always;
 
     location / {
         try_files $uri $uri/ "/Neon Vortex.html";