fix(executor-e2e): invoke .js test fixture via process.execPath on Windows

[Copilot]

Windows has no OS-level shebang support, so spawn('fake-ado-aw.js', args) fires a child error event (ENOENT/ENOEXEC). runner.ts catches the rejection and returns { ok: false }, causing "passes an expected executor rejection without running assertions" to fail with Expected result.ok=true, received false.

Summary

In execute-cli.ts (test-harness only, not shipped in ado-script.zip), resolve .js binaries through process.execPath on Windows before calling spawnCollect:

const [spawnCmd, spawnArgs] =
  process.platform === "win32" && opts.adoAwBin.endsWith(".js")
    ? [process.execPath, [opts.adoAwBin, ...args]]
    : [opts.adoAwBin, args];

The production ado-aw binary is always a native executable — never .js — so the Windows branch is only exercised by test fixtures.

Test plan

• npx vitest run src/executor-e2e/__tests__/runner.test.ts — 3/3 pass
• npm test — 565/565 pass
• npm run typecheck — clean