Add game-simulation package with multi-run balance testing, fix stalled-pipeline trap

Adds a full simulation harness (game-simulation package) with greedy/random strategies,
36-metric diagnostics, multi-run orchestration via child processes, and a statistical
interpreter. Includes 2.3x engine performance optimizations (research bonus caching,
per-DC dirty tracking, reduced allocations in tick pipeline, single-pass loops).

Fixes a critical balance bug where training pipelines stalled on insufficient VRAM would
permanently block training slots — the engine never re-checked stalled pipelines, and the
greedy strategy didn't pre-check VRAM requirements. This caused 20-25% of seeds to get
stuck in Scale-up era. All three fixes (engine un-stalling, strategy VRAM pre-check,
stalled pipeline cancellation) bring pass rate from 75% to 100% across 20 random seeds.

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

packages/game-engine/src/systems/market/enterprisePipeline.ts

@@ -70,7 +70,7 @@ export function processEnterprisePipeline(
   const activeContracts = [...ent.activeContracts];
 
   const effectiveSales = salesHeadcount > 0
-    ? Math.min(1, salesHeadcount * salesEffectiveness / Math.max(1, pipeline.length))
+    ? Math.min(2, salesHeadcount * salesEffectiveness * 0.2)
     : 0;
 
   // --- Lead generation ---
@@ -129,7 +129,8 @@ export function processEnterprisePipeline(
     let transitionProb = baseRate * effectiveSales;
 
     if (lead.stage === 'qualification') {
-      transitionProb *= modelCapability >= lead.requiredCapability ? 1 : 0.1;
+      const capRatio = Math.min(2, modelCapability / Math.max(1, lead.requiredCapability));
+      transitionProb *= capRatio > 1 ? capRatio : capRatio * 0.3;
     } else if (lead.stage === 'poc') {
       const entDemand = enterpriseServingMetrics.demandTokens;
       const entRejected = enterpriseServingMetrics.rejectedTokens;