gas-tools

Add a new GAS global or method mock to the `installGasGlobals()` factory in `packages/gas-test-utils`. Use when a test in any package needs a GAS API that is not yet stubbed (a missing service, or a missing method on an existing service).

Scaffold a new `packages/gas-*` package in this monorepo with the correct structure (src/, package.json, tsconfig.json, README.md, CHANGELOG.md, LICENSE) following existing conventions. Use when adding a new GAS-tooling package to publish under the `@dougborg/*` scope.