v0.3.0

Fixed

• Update windows (manual "Check for Updates…" and background prompts) now come
  to the front instead of opening behind other apps.

Changed

• Builds are now signed with a stable local code-signing identity instead of
  ad-hoc, so a granted Keychain "Always Allow" keeps working across
  auto-updates. (Still not Apple-notarized — fresh installs need a one-time
  Gatekeeper approval, and the 0.2.0 → 0.3.0 update asks for Keychain access
  once more as the identity changes, then persists.)