0.3.0

• Add a versioned, transport-neutral browser renderer protocol with immutable frames, transient
  host events, typed semantic actions, and discoverable target manifests.
• Split the embedded browser host from presentation, ship feature-equivalent Vanilla DOM and Vue
  targets at explicit comparison routes, and refuse transport or persistence APIs inside targets.
• Add shared renderer conformance tests and reproducible Chromium/build benchmarks so framework
  choices can be based on measured bundle, startup, update, memory, install, and build costs.