Add Week 2 depth systems: research, events, competitors, talent, data

Tech tree with 21 research nodes across 5 categories (infrastructure,
efficiency, generation, specialization, safety). Research page with
category-grouped cards, progress tracking, prerequisite gating.

Event engine with 34 events across industry/regulatory/PR/internal/market
categories, weighted random firing, cooldowns, expiry, and choice modal
with consequence preview. Events auto-expire with default choice.

Competitor system with 3 rival AI labs (Prometheus AI, Nexus Labs, Titan
Computing), personality-driven milestone progression, and comparison UI.

Talent page with department hiring, headcount management, and key hire
recruitment from a pool of 10 named characters with special abilities.

Data marketplace with 8 purchasable datasets, user data flywheel from
subscribers, and data system processing in tick loop.

Era transition system checks revenue/capability/reputation thresholds.
All new systems integrated into tick processor with notifications.

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

packages/game-engine/src/systems/eraSystem.ts

@@ -0,0 +1,27 @@
+import type { GameState, Era } from '@ai-tycoon/shared';
+import { ERA_THRESHOLDS } from '@ai-tycoon/shared';
+
+export function checkEraTransition(state: GameState): Era | null {
+  const current = state.meta.currentEra;
+  const eraOrder: Era[] = ['startup', 'scaleup', 'bigtech', 'agi'];
+  const currentIdx = eraOrder.indexOf(current);
+  const nextEra = eraOrder[currentIdx + 1];
+  if (!nextEra) return null;
+
+  const thresholds = ERA_THRESHOLDS[nextEra as keyof typeof ERA_THRESHOLDS];
+  if (!thresholds) return null;
+
+  const bestModel = state.models.trainedModels.reduce(
+    (best, m) => Math.max(best, m.benchmarkScore), 0,
+  );
+
+  if (
+    state.economy.totalRevenue >= thresholds.revenue &&
+    bestModel >= thresholds.capability &&
+    state.reputation.score >= thresholds.reputation
+  ) {
+    return nextEra;
+  }
+
+  return null;
+}