Testnizer v1.4.30

v1.4.30

Signed installers on Windows and macOS — no more "unknown publisher" /
"unidentified developer" warnings. This release also rolls up the v1.4.19
launch-crash fix, so it is the recommended build for everyone.

Signed installers

• Windows: installers are now Authenticode-signed with a Certum Open Source
  code-signing certificate. SmartScreen no longer shows "unknown publisher", and
  the in-app auto-update accepts the signed build.
• macOS: builds are signed with an Apple Developer ID and notarized by Apple,
  so Gatekeeper opens them without the "unidentified developer" block. macOS
  auto-update is working again (the latest-mac.yml manifest is published with
  the build).

Rolled-up launch-crash fix (was v1.4.20, never shipped)

The v1.4.19 "one shared script runtime" change pulled the script libraries into
the app's startup path, where two of them broke the production build. Both are
fixed here:

• App would not start (all platforms): the bundled uuid is ESM-only and
  was left as a runtime require() in the main process, which Electron's Node
  runtime cannot load (ERR_REQUIRE_ESM) — the app crashed before any window
  opened. uuid is now bundled into the main process.
• Blank window: the renderer referenced Node's Buffer global (needed by
  the script libraries) which does not exist in the browser context. A Buffer
  polyfill is now installed before the app loads.

All of the v1.4.19 scripting work (full Chai assertions, the built-in
require() libraries, the legacy Postman interface, Insomnia/Bruno aliases,
Send/Run parity) is intact and now actually runs.

CI hardening: the launch-smoke test that caught the crash now runs on the
Windows and Linux build jobs too (previously macOS only), so a startup crash can
no longer ship undetected on any platform.