Changes

• Add netlify.toml with Cache-Control headers for static assets (WASM/JS/CSS) to reduce bandwidth - WASM files are 60MB and were being re-downloaded on every page load
• Add COOP/COEP headers in netlify.toml for SharedArrayBuffer support (required for WASM multi-threading)
• Add SPA redirect rules for client-side routing
• Update generate-manifest.js to include http://app-provider.localhost:3000 in dev allowed origins (Parcel uses this subdomain)

Tests

Verify caching headers work (after Netlify deploy):

curl -sI https://webzjs.chainsafe.dev/webzjs_wallet_bg.*.wasm | grep Cache-Control

Expected: Cache-Control: public, max-age=31536000, immutable

Verify COOP/COEP headers:

curl -sI https://webzjs.chainsafe.dev | grep -i cross-origin

Expected: Cross-Origin-Opener-Policy: same-origin

Cross-Origin-Embedder-Policy: require-corp

Local dev test:

cd ~/ztest/WebZjs && yarn dev

Open http://localhost:3000, verify snap connects without origin errors

Issues

• Fixes high Netlify bandwidth usage (174GB in Jan vs 27GB in Dec) caused by missing cache headers on 60MB WASM files
• Fixes local dev snap origin rejection for app-provider.localhost:3000