Add rack decommission pipeline stage

Racks can now be marked for decommission from the DC view. The rack
leaves production immediately (freeing slot and power), enters the
pipeline as a timed decommission order, and is removed when complete.

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

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

@@ -36,6 +36,7 @@ function stageTotal(stage: PipelineStage, order: RackOrder): number {
     case 'installation': return timings.installation;
     case 'testing': return timings.testing;
     case 'repair': return RACK_REPAIR_BASE_TICKS;
+    case 'decommission': return timings.installation;
     default: return 0;
   }
 }
@@ -44,7 +45,8 @@ function stageSpeed(stage: PipelineStage, engEff: number, opsEff: number): numbe
   switch (stage) {
     case 'manufacturing': return 1 + engEff * 0.1;
     case 'installation':
-    case 'testing': return 1 + opsEff * 0.1;
+    case 'testing':
+    case 'decommission': return 1 + opsEff * 0.1;
     case 'repair': return 1 + opsEff * 0.05;
     default: return 1;
   }
@@ -88,6 +90,16 @@ export function processInfrastructure(state: GameState): InfraTickResult {
       continue;
     }
 
+    if (order.stage === 'decommission') {
+      const sku = RACK_SKU_CONFIGS[order.skuId];
+      notifications.push({
+        title: 'Rack Decommissioned',
+        message: `${sku.name} rack has been fully decommissioned.`,
+        type: 'info',
+      });
+      continue;
+    }
+
     if (order.stage === 'repair') {
       const total = stageTotal('testing', order);
       rackPipeline.push({
@@ -235,7 +247,7 @@ export function processInfrastructure(state: GameState): InfraTickResult {
       usedPowerKW += sku.powerDrawKW;
     }
 
-    const pipelineRacksForDc = rackPipeline.filter(o => o.dataCenterId === dc.id).length;
+    const pipelineRacksForDc = rackPipeline.filter(o => o.dataCenterId === dc.id && o.stage !== 'decommission').length;
     const usedSlots = totalInDc + pipelineRacksForDc;
 
     const energyCostPerTick = (tierConfig.baseEnergyCostPerTick + usedPowerKW * BASE_ENERGY_COST_PER_FLOP)