Fix recruit: always available, scaling cost; log newest-first at top

recruit_neighbor was gated behind !first_meeting so it vanished after
the first upgrade. Now a single repeatable recruit with scaling cost.
Log scrolls to top on new entries so most recent is always visible.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/ui.ts

@@ -168,11 +168,17 @@ function renderUpgrades(state: State): void {
   }).join('');
 }
 
+let lastLogLength = 0;
+
 function renderLog(state: State): void {
   const log = document.getElementById('log')!;
+  if (state.log.length === lastLogLength) return;
+  lastLogLength = state.log.length;
+  // state.log is newest-first (unshift); render as-is, scroll to top
   log.innerHTML = state.log.map(e =>
     `<div class="log-entry ${e.kind}">${e.text}</div>`
   ).join('');
+  log.scrollTop = 0;
 }
 
 function showOverlay(state: State): void {