Make EmptyState.action required (or typed as ReactNode with stub) to enforce baseline-ui MUST rule

[Ryan-Atkinson87]

Context

PR #181 introduced EmptyState in orchestrator-ui/src/components/StateViews.tsx with action as an optional prop:

export function EmptyState({
  message,
  action,
  className,
}: {
  message: string;
  action?: ReactNode;
  className?: string;
})

The baseline-ui skill specifies: "MUST give empty states one clear next action."

Making action optional at the type level means future feature screens can render an EmptyState with no action and pass type-checking, silently violating the baseline rule.

What to do

Either:

• Make action required (action: ReactNode) — callers must supply one, even if it's just a navigation link; or
• Keep it optional but add a runtime console.warn when action is undefined in dev mode

The first option is preferred — it enforces the rule at the type level without any runtime overhead.

Non-blocking — no existing callers are affected (none yet in feature screens #61–#68).