Add three-member short alliance prototype

components/coalition-nexus.tsx

@@ -11,7 +11,7 @@ export type CoalitionNexusView = {
   proposal: CoalitionAdmission | null;
   revision: number;
   /** Absent preserves the original, at-most-three alliance prototype. */
-  variant?: 'unlimited';
+  variant?: 'three-short' | 'unlimited';
   /** Until group admission can reconcile a live bribe commitment, only
    * departure remains available in this Nexus. */
   admissionBlocked?: boolean;
@@ -69,6 +69,7 @@ export function CoalitionNexus({ view, disabled = false, onIntent }: {
   const submit = (intent: CoalitionNexusIntent) => { if (!disabled) onIntent(intent); };
   return <section aria-label="Group alliance negotiations" className="notice min-w-0 space-y-3 break-words">
     <h3>Group alliance negotiations</h3>
+    {view.variant === 'three-short' && <p>Alliances can have up to three members and need three strongholds to win.</p>}
     {view.variant === 'unlimited' ? <p>Every current member and the invited player must agree.
       The existing alliance remains in place while an invitation is pending.</p> :
       <p>All three players must agree before an invitation forms an alliance.