Remove `ts-node` in favor of native TS support

[ecraig12345]

Node 22.18 introduces support for natively running TypeScript in many cases, so we don't need ts-node any more. This may require some migration work from partners to update their config syntax but it should have the benefit of being much faster.

• remove all ts-node references in code and docs
• update docs to link to the Node docs on requirements of native TS support - https://nodejs.org/docs/latest-v22.x/api/typescript.html#type-stripping
• ensure the way we import configs works with ESM
• add support for detecting just.config.<cjs|mjs|cts|mts>
• add related tests