fix: edge runtime WASM bindings for satori yoga and resvg

[harlan-zw]

🔗 Linked issue

Related to #434

❓ Type of change

• 📖 Documentation
• 🐞 Bug fix
• 👌 Enhancement
• ✨ New feature
• 🧹 Chore
• ⚠️ Breaking change

📚 Description

Edge runtimes (Cloudflare Workers, Vercel Edge) were failing to generate OG images because satori's yoga WASM binary was resolved from yoga-wasm-web instead of satori/yoga.wasm — the correct binary that matches satori's bundled Emscripten glue. Also fixes Cloudflare Workers blocking WebAssembly.instantiate() by patching calls to use synchronous new WebAssembly.Instance() for pre-compiled modules.

Key changes:

• Yoga WASM: resolve from satori/yoga.wasm via #og-image/yoga-wasm alias
• CF Workers: patch WebAssembly.instantiate → new WebAssembly.Instance using oxc-walker AST traversal
• Vercel Edge: patch unenv Process polyfill (Proxy + private class fields incompatibility)
• Bundle size: mock unused renderer bindings to avoid bundling large WASM files (e.g. takumi 3.4MB) for renderers that aren't used
• Tests: cloudflare-satori and vercel-edge-satori e2e test fixtures

[harlan-zw]

Code review

Found 1 issue:

1. $fetch fallback reintroduces self-referencing subrequest on CF Workers. The new fallback path in cloudflare.ts calls $fetch(fullPath, { baseURL: origin }) when event.$fetch is unavailable. This makes an outbound HTTP request to the worker's own origin -- the exact pattern that commit ce307ff8 previously removed with the comment: "Use event.$fetch for in-process resolution -- avoids external HTTP round-trips which are unreliable on CF Workers (self-referencing subrequests)". If a CF Workers deployment reaches this fallback (no ASSETS binding, no event.$fetch), font loading will fail or hang due to self-referencing subrequest restrictions.

og-image/src/runtime/server/og-image/bindings/font-assets/cloudflare.ts

Lines 24 to 35 in 3af1ada

	// Fallback: use event.$fetch for in-process resolution when available,
	// otherwise fall back to $fetch with origin (for presets without ASSETS binding)
	const internalFetch = (event as any).$fetch as ((path: string, opts: { responseType: string }) => Promise<ArrayBuffer>) | undefined
	if (typeof internalFetch === 'function') {
	const arrayBuffer = await internalFetch(fullPath, { responseType: 'arrayBuffer' })
	return Buffer.from(arrayBuffer)
	}
	const origin = getNitroOrigin(event)
	const arrayBuffer = await $fetch(fullPath, {
	responseType: 'arrayBuffer',
	baseURL: origin,
	}) as ArrayBuffer

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[adamdehaven]

@harlan-zw can this be released on the v3.x release? We're currently also getting a 500 on Cloudflare