fix(hir/codegen): new <imported-function>() runs the constructor body (zod v4 checks; #4698)

[proggeramlug]

Summary

Fixes #4698. new F(args) where F is a function — or a const/let holding a closure value — imported from another module silently produced an empty object: the constructor body never ran, so this.x = … and Object.defineProperty(this, …) writes were lost.

This is the zod-v4 TypeError: Cannot read properties of undefined (reading 'onattach') crash. Every string/number schema with a check (.min / .max / .length / .regex / numeric .gt / .lt / …) builds its check via new checks.$ZodCheckMinLength(def) across the core/checks.ts → core/api.ts module boundary (where checks is an import * as namespace), so the check instance came back with its non-enumerable _zod property (and everything else) gone — then crashed on ch._zod.onattach.

Note: the original issue analysis suspected a defineProperty attribute-retention bug. The real cause is the cross-module new path; a minimal new <imported closure>() loses all own properties because the constructor body is skipped entirely.

Root cause

An imported binding is neither a local, a func, nor a class in the importing module, so it fell through to Expr::New { class_name } — whose codegen finds no matching class and emits an empty placeholder — instead of js_new_function_construct, which binds this, runs the body, and returns the populated instance. Three gaps, all on the cross-module new path:

• perry-hir lower/expr_new.rs — bare new <importedFn>() now routes to NewDynamic { callee: ExternFuncRef, … } when the name resolves via lookup_imported_func, mirroring the existing local / FuncRef branches.
• perry-codegen expr/new_dynamic.rs — ExternFuncRef added to the routes_through_function_construct callee set so it reaches js_new_function_construct instead of the best-effort empty-object fallback.
• perry-codegen expr/v8_interop.rs::try_static_class_name — new ns.Foo() over a namespace import only takes the class-construction path when Foo actually names a known class; a closure-valued const export (zod's $ZodCheckMinLength = $constructor(...)) now falls through to the function-construct route. Real namespace-imported classes (in ctx.classes) and re-exported builtins (intercepted by the helper's global thunks) are unaffected.

Verification

The exact repro now matches Node:

import { z } from "zod";
console.log(z.string().min(2).parse("hello")); // → hello

.max / .length / .regex / numeric .gt / .lt and nested object schemas with checks all match Node byte-for-byte. Minimal multi-module + namespace-import repros pass; real namespace-imported classes still construct correctly.

• perry-hir + perry-codegen unit tests: pass.
• Class parity filter: test_issue_836_zod_class_reexports (cross-module class re-export, directly in the change's blast radius) passes. The pre-existing class-suite failures (iterators, mixins, defineProperty-on-prototype, stream subclass) are single-file programs with zero imports — and all three changes here require a cross-module import to fire, so they are provably inert for those files.

Out of scope

The safeParse error-path / .email() error-formatting failures noted in #4698 are a separate, still-open issue.

Refs #793.