just-task config.ts should support ESM configs

Right now, just-scripts only works with commonjs configs. Given how the ecosystem is moving to esm, this will become a point of frustration.

If you have a package with type: "module" set right now, you'd expect just.config.js to be an ESM.

just-task will throw:

yarn run v1.22.17
warning package.json: No license field
$ just-scripts build
[5:06:17 PM] x Invalid configuration file: D:\git\cloudpack2\packages\path-utilities\just.config.js
[5:06:17 PM] x Error: Error [ERR_REQUIRE_ESM]: require() of ES Module D:\git\cloudpack2\packages\path-utilities\just.config.js from D:\git\cloudpack2\node_modules\just-task\lib\config.js not supported.
Instead change the require of just.config.js in D:\git\cloudpack2\node_modules\just-task\lib\config.js to a dynamic import() which is available in all CommonJS modules.
    at Object.readConfig (D:\git\cloudpack2\node_modules\just-task\lib\config.js:30:34)
    at Object.<anonymous> (D:\git\cloudpack2\node_modules\just-task\lib\cli.js:37:31)
    at Object.<anonymous> (D:\git\cloudpack2\node_modules\just-scripts\lib\cli.js:3:1)
    at Object.<anonymous> (D:\git\cloudpack2\node_modules\just-scripts\bin\just-scripts.js:2:1)

I think the require statement can change to an async import, but that will also require some shuffling in the CLI to await on results (or Promise chain.) Plus I'm not sure how this will affect importing commonjs results - that will still need testing.

Start with just-task/lib/config.js and its readConfig function, then trace how results flow through just-task/lib/cli.js and just-scripts/lib/cli.js. Verify the CLI can await configuration loading, preserve CommonJS support, and load an ESM just.config.js for packages using type: "module".