doc: add cloudflare worker example readme

examples/cloudflare-worker/README.md

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+# Cloudflare Worker Example
+
+For this example, we will be using the [Cloudflare Worker](https://workers.cloudflare.com/) platform to upgrade images to WebP.
+
+We can use the latest Wrangler CLI to run the example locally and deploy it to Cloudflare Workers.
+
+## Running the example locally
+
+1. Run `npm install`
+2. Run `npm run start` to start the development server
+
+## Usage of jSquash packages in Cloudflare Worker
+
+One caveat is wrangler won't dynamically bundle the WASM modules with the worker.
+
+You will need to ensure you configure the Worker to set these as global variables in the [wrangler.toml](wrangler.toml) file.
+```
+# wrangler.toml
+[wasm_modules]
+# Manually specify the path to the WASM module for each codec
+JPEG_DEC_WASM = "node_modules/@jsquash/jpeg/codec/dec/mozjpeg_dec.wasm"
+```
+
+The `encode` and `decode` modules both export an `init` function that can be used to manually load the wasm module.
+
+```js
+import decode, { init as initJpegDecode } from '@jsquash/jpeg/decode';
+
+const WASM_MODULE = // A WebAssembly.Module object of the compiled wasm binary
+await initJpegDecode(WASM_MODULE);
+const image = await fetch('./image.jpeg').then(res => res.arrayBuffer()).then(decode);
+```