Automate a clean-machine install smoke for dispatch

[galligan]

Why

v0.2.0 proved the package can install and run locally, but the adoption path still deserves a repeatable clean-machine smoke that catches PATH, package asset, daemon, and first command regressions before release.

Scope

Turn the documented first-run path into a repeatable smoke check for installed dispatch.

Acceptance criteria

• Define the clean install path: install -> dispatch doctor -> dispatch up -> one basic command -> dispatch down.
• Run the smoke against an installed artifact (uv tool install outfitter-dispatch or a built wheel), not just in-tree uv run.
• Use isolated temp DISPATCH_HOME/Codex state where possible and avoid touching live user sessions.
• Make expected warning states explicit when Codex auth or App Server access is unavailable.
• Add the smoke to CI/release checks if it can be reliable there; otherwise add a maintainer-run script with documented constraints.
• Update release docs so maintainers know exactly when and how to run it.

Notes

Keep live App Server usage cheap and conservative. If a full live Codex chat is required, use a tiny prompt, lesser model, minimal reasoning, and clearly bounded cleanup.