fix: upload client does not need cors mode on presigned url put (#1295)

Apparently some fetch implementations may not have "mode", which is the
case for Cloudflare Workers for instance. CF worker deploying
upload-client is now failing because this "mode" is set. You can also
read more about the general problem in
aws/aws-sdk-js-v3#1165

In summary, "mode" may not be implemented in fetch, but the default
appears to be cors anyway so this could be deleted without loss of
functionality:
https://developer.mozilla.org/en-US/docs/Web/API/Request/mode#default_mode.

Related to #1273

packages/upload-client/src/store.js

@@ -98,7 +98,6 @@ export async function add(
       try {
         const res = await fetchWithUploadProgress(responseAddUpload.url, {
           method: 'PUT',
-          mode: 'cors',
           body: car,
           headers: responseAddUpload.headers,
           signal: options.signal,

packages/w3up-client/README.md

@@ -34,6 +34,7 @@ This library is the user-facing "porcelain" client for interacting with w3up ser
     - [Client-server](#client-server)
     - [Delegated](#delegated)
     - [User owned](#user-owned)
+  - [Environments requiring wasm import](#environments-requiring-wasm-imports)
 - [API](#api)
 - [Contributing](#contributing)
 - [License](#license)
@@ -395,6 +396,12 @@ sequenceDiagram
 - There is a world of possibilities with your users "bringing their own identity" for their Space; you could explore how crypto wallet private keys, Apple Passkey, and more might map to Space DIDs and have the client use those
 - If you have code snippet(s) that works for you, please share them in a PR or [Github issue](https://github.com/web3-storage/w3up/issues) and we'll link them here!
 
+### Environments requiring wasm import
+
+Some environments (for instance Cloudflare Workers) require wasm bytecode to be imported. All other paths to load wasmm are disallowed by embedder. For these use cases, the default export of `w3up-client` (most compatible) won't work out of the box. A custom build will need to be created to get the client working.
+
+We created a `esbuild-plugin` [esbuild-plugin-w3up-client-wasm-import](https://github.com/vasco-santos/esbuild-plugin-w3up-client-wasm-import) that you can easily use. There is also an [example repository](https://github.com/vasco-santos/worker-w3up-client-example).
+
 ## API
 
 - [`create`](#create)