docs(rfcs): review RFCs for drift from the implementation #3396

Documentation is

• Missing
• Outdated
• Confusing
• Not sure

Explain in Detail

Several RFCs in rfcs/ have drifted from the implementation. voidzero-dev/vite-plus#3383 fixed the .nvmrc part, and listed other gaps it left out:

• rfcs/env-command.md: the CLI usage comment # Pin a specific version in current directory (creates .node-version) predates the devEngines.runtime default target.
• rfcs/env-command.md: the "Pin Command" section covers Node pins only. --target package-manager isn't mentioned.
• rfcs/dev-engines.md: the decision table (row 4) lists only --target node-version / --target dev-engines.

These were found while working on one topic, so there are likely more. Some RFCs also mix the original decision with later revisions (e.g. "Breaking revision: unified environments" in rfcs/env-command.md), so it's unclear which parts should track the implementation.

Your Suggestion for Changes

Ideally, the team reviews the RFCs as a whole, since it knows which decisions changed and why. It could also clarify whether RFCs are living specs or historical records — the dev-engines.md decision table was left unchanged in #3383 for that reason.

If that's not feasible, I can continue with follow-up PRs, one topic each.

@liangmiQwQ, following up on your comment here, since replying in the merged PR would be noise.

Relevant Page

https://github.com/voidzero-dev/vite-plus/tree/main/rfcs