refactor: cut the hand-rolled deepEqual and dead scaffolding

[btravers]

A ponytail audit of the whole tree, applied. +25 / −231 lines, no new dependencies.

The one decision to make

equals now delegates to node:util's isDeepStrictEqual instead of a 172-line hand-rolled traversal. Every case equal.spec.ts pins passes against it unchanged — bigint, Set/Map by contents, nested key order, typed arrays and ArrayBuffer bytewise, RegExp, Date, and both cyclic-value tests (including the Set-matching poison cases).

Two consequences, both in the changeset:

• This makes the package Node-only. A browser or edge bundle without a node:util shim will no longer resolve it. There is no browser field today and nothing else imports a node: builtin, so this is the first such constraint. If browser consumers matter, this commit is the one to drop.
• +0 and -0 now compare unequal (Object.is) where SameValueZero made them equal. No test pinned it.

The rest

Cut	Why
Two of three JSON-LD blocks in the docs head	WebSite and Organization restated title/url/logo VitePress already emits; "entity" is not an Organization
test:types script / turbo task / package script	CI runs format, lint, typecheck, test, knip, build — and typecheck already runs the .test-d.ts pass. Confirmed against btravstack/config's ci-reusable.yml
IsAtLeastAsWideAs	Inlined at its two uses in IsNarrowLiteral
RootInstance's duplicate intersection	Now ConstructedInstance<string, S, A> — same type, one definition
schemaOf	One call site; inlined into shape()
Array.isArray(values) in discriminantValues	zod v4 gives a Set for z.literal(...).values and undefined for z.enum(...).values — measured, no schema reached it

Tried and reverted

A shared root vitest.shared.ts replacing four byte-identical configs. Tests ran fine, but knip discovers spec files through each package's own vitest config, so consolidating made it report all 16 spec files and 5 devDependencies as unused. Teaching knip costs more config than the 21 duplicate lines it saves.

Verification

Full gate green in gate order: format --check, lint, typecheck (all four billing-domain steps, both compilers, plus the emitted-.d.ts check), 179 + 18 tests, knip, build.

The declaration-emit acceptance rules were re-measured rather than assumed: zeroGeneratedKeys< / ImmutableKeys< in the consumer emit set, and the RootInstance alias made index.d.mts47 bytes smaller (40,768 → 40,721), measured by building both ways.

Not cut, checked and justified in the audit: freeze.ts's schema-directed passthrough walk (every branch is spec-pinned, and removing it re-freezes objects the caller still owns), the *Src alias block in entity.ts, the ten top-level type re-exports in index.ts, and the double-compiler emit gate.

[Copilot]

Pull request overview

This PR refactors @btravstack/entity to remove dead scaffolding and replace the hand-rolled deep equality implementation with Node’s node:utilisDeepStrictEqual, while also pruning unused scripts/tasks and a few type/util helpers.

Changes:

• Replace the previous deepEqual traversal with node:util’s isDeepStrictEqual for Entity#equals, and update tests accordingly (making the package Node-only).
• Remove the test:types turbo task and package scripts, relying on the existing typecheck pipeline to run the .test-d.ts pass.
• Inline/remove small helpers and simplify a few internal types/utilities (schemaOf, IsAtLeastAsWideAs, RootInstance aliasing).

Reviewed changes

Copilot reviewed 13 out of 13 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
turbo.json	Removes the test:types task from the turbo pipeline.
packages/entity/src/union.ts	Removes an unreachable discriminant .values array fallback (zod v4 measured behavior).
packages/entity/src/types.ts	Simplifies RootInstance to reuse ConstructedInstance<string, S, A>.
packages/entity/src/shape.ts	Inlines schemaOf behavior using isFieldSpec for unwrapping field specs.
packages/entity/src/field.ts	Deletes schemaOf helper (now inlined at call site).
packages/entity/src/equal.ts	Deletes the hand-rolled deep equality implementation.
packages/entity/src/equal.spec.ts	Switches equality spec assertions to use node:utilisDeepStrictEqual.
packages/entity/src/entity.ts	Implements equals via isDeepStrictEqual and updates the rationale doc comment.
packages/entity/package.json	Removes test:types script (keeps .test-d.ts under typecheck).
package.json	Removes root-level test:types script.
docs/.vitepress/config.ts	Removes redundant JSON-LD blocks from the docs head.
CLAUDE.md	Updates architecture notes to reflect the removal of equal.ts and Node-only equality.
.changeset/lazy-pans-brake.md	Documents the Node-only change and the +0 vs -0 equality behavior change.

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