chore: cut 1.0.0 release with usage docs and MIT license

Bump APP_VERSION to 1.0.0 / BUILD_NUMBER to 1; refresh README to clarify
project direction and add quarantine-removal guidance for the unsigned
release artifact; add USAGE.md as the end-user walkthrough; add MIT LICENSE.

scripts/build-app.sh

@@ -6,8 +6,8 @@ cd "$(dirname "$0")/.."
 
 APP_NAME="OpenLess"
 BUNDLE_ID="com.openless.app"
-APP_VERSION="0.1.8"
-BUILD_NUMBER="9"
+APP_VERSION="1.0.0"
+BUILD_NUMBER="1"
 BUILD_DIR="build"
 APP_DIR="${BUILD_DIR}/${APP_NAME}.app"
 BIN_DIR="${APP_DIR}/Contents/MacOS"