Add JSON output to dispatch version

[jongio]

Problem

dispatch version prints only the raw version string. Install scripts, package checks, and status dashboards need a machine-readable form and currently have to wrap or parse plain text.

Proposed solution

Add dispatch version --json and dispatch --version --json. The command should print a small JSON object with the current version. The plain text form should stay unchanged.

Acceptance criteria

• dispatch version --json prints { "version": "..." } with a trailing newline.
• dispatch --version --json prints the same JSON object.
• dispatch version and dispatch --version keep the current plain text output.
• Unknown version flags return a clear error.
• Tests cover both JSON entry points and the existing plain text path.

Complexity

S

Priority

Medium