fix: guard process usage for native browser ESM

[constayush]

Problem

Importing motion-utils directly in the browser as a native ES module throws
ReferenceError: process is not defined.

This happens because process.env.NODE_ENV is accessed at module evaluation
time without guarding for non-Node environments. The issue is masked when usin
bundlers that inject a process polyfill, but fails in pure browser ESM

Solution

Guard access to process before reading process.env.NODE_ENV so the code can
run safely in browsers while preserving existing behavior for Node and bundler
environments.

Result

• Native browser ES module imports no longer throw
• No behavior change for production builds
• No reliance on bundler polyfill

Fixes : #3417

[stefanpearson]

Thanks!

[stefanpearson]

I've noticed a few other 'unsafe' references to process.env across various files in the motion packages. I'm assuming they will need updating too? https://github.com/search?q=repo%3Amotiondivision%2Fmotion%20process.env&type=code

[constayush]

I dont think so as most of them are node only files so it should not be a problem , but yeah there are 'unsafe' references to process.env inside /src like Hooks, utils, render logic, that should be guarded as they ll be run in browser.