TypeScript module throws `RangeError: Internal error. Icu error.` procedure when trying to use http

[doodlechaos]

Bug: TypeScript module V8 runtime throws RangeError: Internal error. Icu error. on Windows (breaks Intl/URL and ctx.http.fetch)

Summary
On Windows, a SpacetimeDB TypeScript server module throws RangeError: Internal error. Icu error. when calling ICU-dependent JS functionality (e.g. "a".localeCompare("b")) and also when constructing a URL (new URL("https://example.com")). This breaks ctx.http.fetch(...) (HTTP requests), so TS procedures cannot call external apis in some cases (e.g. OpenAI in my use case).

Environment

• OS: Windows 11

spacetime Path: C:\Users\merob\AppData\Local\SpacetimeDB\bin\current\spacetimedb-cli.exe
Commit: bbfa851b45db7096aa2a69d7dbad84f52983559f
spacetimedb tool version 1.11.1; spacetimedb-lib version 1.11.1;

Impact

• Any ICU/Intl usage appears broken (localeCompare, likely Intl.*, toLocaleString, etc.)
• URL parsing/creation is broken (new URL(...))
• ctx.http.fetch(...) fails with the same ICU error, preventing HTTP requests from procedures

Minimal reproduction
Create a TS module with the following code and call the procedure from a client:

// spacetimedb/src/command.ts
import { t } from "spacetimedb/server";

export function registerCommandProcedures(db: { procedure: Function }) {
  db.procedure("icu_smoketest1", {}, t.string(), (_ctx: any) => {
    try {
      "a".localeCompare("b"); // << Triggers the error. This does too: new URL("https://example.com"); //<< Triggers the error
      return "OK";
    } catch (e: any) {
      return `ICU FAIL: ${String(e?.message ?? e)}`;
    }
  });
}

Client:

  async function onTestClick() {
    console.log("Sending test command to server");
    let result = await conn.procedures.icuSmoketest1({});
    console.log("Result:", result);
  }

Sending test command to server
App.svelte:52 Result: ICU FAIL: Internal error. Icu error.