Add intellisense and fix side-effects

[jerriclynsjohn]

As we need to use Tier on edge, we had to import the edge-compliant Tier using import {Tier} from 'tier/client', while the entire codebase compiles it renders IDE intellisense useless for fetching Tier SDK documentation and autocomplete.

We fix this by changing tsconfig.json

- "moduleResolution": "Node"
+ "moduleResolution": "NodeNext"

Now that the intellisense is working, there are two side effects that need attention

1. T3 env validation of schema on build (https://env.t3.gg/docs/nextjs)

• We cannot import mjs file into a common JS file, so we had to rename env.mjs to env.js, because of this change we cannot import our env file into next.config.mjs and we have to remove it for now.

2. @headlessui/react - This doesn't break compilation but inherently resurfaces the below mentioned issues

• Not compatible with NodeNext #1699
• Property panel does not exist #1419