docs: separate the dev and consumer Node floors

[camcima]

Follow-up to #56. Documentation only — no code or config changes.

While cleaning up after #56 merged, a release-it --dry-run surfaced a contradiction waiting for the next release.

The problem

Commit 4c0a23c (July 7, unreleased) carries:

BREAKING CHANGE: minimum supported Node.js is now 22.13 (was 20).

But it only changed two things: the private root package.json and the CI runner version. No published package was touched — all six still declare engines: >=20, and #56 added a compat job that verifies that claim by loading every built bundle on Node 20.

So the next release would announce a consumer-facing break that never happened, while shipping packages that say the opposite.

The resolution

The two floors are both correct, because they describe different audiences:

Where	Node	Why
Developing this repo	≥ 22.13	pnpm 11 loads node:sqlite, which doesn't exist before 22.13
Consuming a published package	≥ 20	What the built bundles actually need — verified in CI and against real Node 20.19.1

The root package.json is private: true, so its engines never reaches consumers. Raising the packages to match it would drop Node 20 users on a toolchain-parity argument rather than a technical one.

This PR records that reasoning so the mismatch doesn't read as an oversight and get "fixed" later, and adds a release checklist item to strike the stale bullet from the generated CHANGELOG.md before the next release goes out.

Changes

• CONTRIBUTING.md — a Node versions section explaining the split, and a Releasing section documenting pnpm release / --dry-run plus the one-time changelog note.
• README.md — the requirements section now distinguishes the consumer floor from the contributor one. The >=20 badge is unchanged and correct.

Verification

• pnpm format:check and pnpm lint clean.
• scripts/smoke-test.mjs re-run against real Node 20.19.1 to confirm the >=20 claim still holds.

Also worth a decision (not in this PR)

The same dry run computes the next version as 1.0.0 — conventional-changelog treats the breaking changes from #56 as major even at 0.x. If you'd rather ship 0.3.0, that needs a --preRelease-style override or an explicit version at release time; it isn't something this PR changes.

🤖 Generated with Claude Code

https://claude.ai/code/session_01MsFZHTnQmAUMjtLUegFRPL

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 100.00%. Comparing base (c744492) to head (f32f105).

Additional details and impacted files

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  Coverage   100.00%   100.00%           
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  Files           11        11           
  Lines          695       695           
  Branches       167       167           
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  Hits           695       695           

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