fix(cli): launch Biome reliably in Windows architecture guards #881

Following the request in #863 (comment), this tracks the launcher defect separately from architecture path normalization.

At 83b0246e532d3f76491baabbc8b0b266f00e3590, cli/tests/architecture/biome-guards-bite.arch.test.ts builds BIOME from node_modules/.bin/biome and passes that path directly to spawnSync. On native Windows the launch returns status: null and error.code: ENOENT. Invoking the installed package through Node succeeds with exit 0 and prints Version: 2.5.11.

Environment: Windows, Node 22.23.1, pnpm 12.3.4 for the latest architecture-suite run. Existing dependencies were originally installed with pnpm 11.19.0 and --ignore-scripts; this is not a claim of a fresh installation under 12.3.4.

From cli/, this launch-only reproduction uses the same installed dependency for both attempts:

import { spawnSync } from "node:child_process";
import { resolve } from "node:path";

const direct = spawnSync(resolve("node_modules/.bin/biome"), ["--version"], {
  encoding: "utf8",
});
const viaNode = spawnSync(process.execPath, [
  resolve("node_modules/@biomejs/biome/bin/biome"), "--version",
], { encoding: "utf8" });
for (const [name, result] of [["shim", direct], ["node", viaNode]]) {
  console.log(name, result.status, result.error?.code, result.stdout, result.stderr);
}

biomeFindings() does not inspect result.error or verify that the process started. It parses stdout/stderr and returns [] after a failed launch, which is indistinguishable from a successful invocation with no findings to a caller expecting a clean result. The planted positive cases do fail: the three tests for process.exit, process globals, and default exports all receive empty arrays instead of their expected diagnostics.

Expected: use a launcher that works on supported platforms, and surface process-start failures as explicit failures before parsing findings. Preserve ordinary nonzero lint results, since those carry the violations the guard is designed to assert.

The control above proves only executable startup, not lint correctness. No Biome launcher changes are included in the separate path-normalization contribution.

Affected file: cli/tests/architecture/biome-guards-bite.arch.test.ts

AI tool: Codex. CLI checkout version: 5.3.0. OS: Windows. Path normalization PR: #880.