fix: complete zod/v4 migration (supersedes #158)

[mcampa]

Supersedes #158 by rebasing onto current master and fixing the CI failure.

Summary

#158 widens the zod peer dependency to `^3.25.0 || ^4.0.0` and switches `src/` imports from `'zod'` to `'zod/v4'`, per the zod docs for package authors. That PR fails CI with a `tsc` OOM, because all `test/` files still `import { z } from 'zod'`. TypeScript treats `ZodObject` from `'zod'` and `'zod/v4'` as nominally distinct types — even though they resolve to the same runtime class in `zod@4.0.14` — and the mismatch explodes type instantiation through tRPC's generic `Procedure`/`Router` machinery via `OpenApiMeta`, exhausting Node's heap.

See investigation: #158 (comment).

Changes

1. Follow zod guidance on supporting v4 - for users incrementally migrating from v3 #158 commits, rebased onto current master (preserves the `OpenApiContactObject`/`OpenApiLicenseObject` code from feat: add contact and license to GenerateOpenApiDocumentOptions #157)
2. Test files updated to `'zod/v4'` — 8 files, mechanical `sed` replacement, resolves the OOM
3. Cast on one test's examples meta — `test/generator.test.ts` uses the v3-style `{ Lily: ..., John: ... }` named-object form for `.meta({ examples })`. zod-openapi v5 types this as `unknown[]`, but the runtime still accepts the record form. Cast preserves existing behavior.

Test plan

• `pnpm exec tsc --noEmit` passes in ~2s (no OOM)
• `pnpm run build` succeeds (full build pipeline: tsc + jest + cjs + esm)
• All 129 tests passing across 8 suites
• CI green

🤖 Generated with Claude Code

[Copilot]

Pull request overview

This PR completes the Zod v4 “permalink import” migration by switching internal and test-suite Zod imports to zod/v4 and widening the package’s zod peer dependency to support both zod@^3.25 and zod@^4.

Changes:

• Widen zod peer dependency to ^3.25.0 || ^4.0.0.
• Migrate src/ and test/ Zod imports from zod to zod/v4 to prevent nominal type mismatches (and the resulting tsc OOM).
• Adjust one test’s .meta({ examples }) typing to compile under the updated zod-openapi typings.

Reviewed changes

Copilot reviewed 15 out of 15 changed files in this pull request and generated 6 comments.

Show a summary per file

File	Description
package.json	Widens zod peer dependency range to support ^3.25 and ^4.
src/utils/zod.ts	Switches Zod imports to zod/v4 for consistent typing/runtime.
src/utils/procedure.ts	Switches Zod imports to zod/v4 for consistent typing/runtime.
src/types.ts	Updates ZodObject type import to come from zod/v4.
src/generator/schema.ts	Switches Zod imports to zod/v4 for consistent schema generation typing.
src/generator/index.ts	Switches ZodSchema import to zod/v4 for defs typing.
src/adapters/node-http/core.ts	Switches Zod imports to zod/v4 to keep runtime checks/types consistent.
test/generator.test.ts	Updates import to zod/v4 and adds a type assertion for .meta({ examples }).
test/adapters/standalone.test.ts	Updates Zod import to zod/v4 to avoid nominal mismatches in tests.
test/adapters/nuxt.test.ts	Updates Zod import to zod/v4 to avoid nominal mismatches in tests.
test/adapters/next.test.ts	Updates Zod import to zod/v4 to avoid nominal mismatches in tests.
test/adapters/koa.test.ts	Updates Zod import to zod/v4 to avoid nominal mismatches in tests.
test/adapters/fetch.test.ts	Updates Zod import to zod/v4 to avoid nominal mismatches in tests.
test/adapters/fastify.test.ts	Updates Zod import to zod/v4 to avoid nominal mismatches in tests.
test/adapters/express.test.ts	Updates Zod import to zod/v4 to avoid nominal mismatches in tests.

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[mcampa]

Addressed all 6 Copilot review comments in 4ab0e19:

• Type-only imports — `ZodSchema`, `ZodObject`, `ZodAny`, `ZodRawShape`, `ZodType`, `ZodError` are all used only in type positions. Split them into `import type` declarations across the 5 source files. Keeps `z` (and `ZodArray` for the `instanceof` checks) as value imports.
• Unused `ZodTypeAny` in `src/adapters/node-http/core.ts` — removed.
• `as never` cast in `test/generator.test.ts` — replaced with `as unknown as unknown[]` and added a comment explaining why the runtime still accepts the v3-style named-record form even though zod-openapi v5 types `meta.examples` as `unknown[]`.

`pnpm run build` (tsc + jest + cjs + esm) green: 129/129 tests passing, full build succeeds.