Standalone Greeter Demo

This demo proves the SDK can run without HiveCast, without a managed platform, and without committed credentials.

Run from the repository root:

pnpm demo:standalone

What it proves:

the SDK packages build from this repo,
this package builds against @open-matrix/core,
matrix run starts the actor from the package manifest,
matrix invoke demo.greeter echo ... calls the actor over the SDK local runtime path,
all runtime state is written under the demo package's local .matrix/ directory.