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/servingPipeline.ts

@@ -68,13 +68,18 @@ function buildModelFleet(
 ): ModelServingSlot[] {
   const slots: ModelServingSlot[] = [];
 
-  const deployedBases = modelsState.baseModels.filter(m => m.isDeployed);
-  const deployedVariants: { variant: ModelVariant; baseModel: BaseModel }[] = [];
+  const deployedBases: BaseModel[] = [];
+  const baseModelById = new Map<string, BaseModel>();
+  for (const m of modelsState.baseModels) {
+    if (m.isDeployed) deployedBases.push(m);
+    baseModelById.set(m.id, m);
+  }
 
+  const deployedVariants: { variant: ModelVariant; baseModel: BaseModel }[] = [];
   for (const family of modelsState.families) {
     for (const variant of family.variants) {
       if (!variant.isDeployed) continue;
-      const base = modelsState.baseModels.find(m => m.id === variant.baseModelId);
+      const base = baseModelById.get(variant.baseModelId);
       if (base) deployedVariants.push({ variant, baseModel: base });
     }
   }
@@ -173,7 +178,9 @@ function serveFromFleet(
   let degraded = 0;
   let qualityWeightedSum = 0;
 
-  const bestQuality = fleet.length > 0 ? Math.max(...fleet.map(s => s.qualityScore)) : 1;
+  let bestQuality = 0;
+  for (const s of fleet) { if (s.qualityScore > bestQuality) bestQuality = s.qualityScore; }
+  if (bestQuality === 0) bestQuality = 1;
   const degradationActive = policy.autoDegradation.enabled && overallUtilization > policy.autoDegradation.triggerThreshold;
 
   for (const slot of fleet) {