Separate editable image sources from generated commit revisions and loaded actor implementations. Add the source filesystem and context actions in VS Code, path-based REPL commands, sender-aware actor contexts, and privileged lifecycle controls.
BREAKING CHANGE: protocol v4 replaces published behavior commands with image source paths and commit operations. Actor handlers now use handle(ctx, state, sender, message) and return only state; outgoing messages use ctx.send or ctx.send_from.
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
