fix(merge): resolve post-merge type errors from batch-1 agents

- ScenarioPlanner.Baseline.shortCode: string → string | null (matches Prisma)
- ScenarioPlanner.SimulationResult.chargeabilityTarget: number → number | null
- Remove runtime Zod parse from scenario procedures (typed by Prisma already)
- Float64Array index access: add non-null assertions for noUncheckedIndexedAccess

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

packages/staffing/src/capacity-analyzer.ts

@@ -59,8 +59,8 @@ export function analyzeUtilization(input: CapacityAnalysisInput): UtilizationAna
     const lo = aStartDay - startDay;
     const hi = aEndDay - startDay;
     for (let i = lo; i <= hi; i++) {
-      allocHours[i] += alloc.hoursPerDay;
-      if (alloc.isChargeable) chargeHours[i] += alloc.hoursPerDay;
+      allocHours[i]! += alloc.hoursPerDay;
+      if (alloc.isChargeable) chargeHours[i]! += alloc.hoursPerDay;
     }
   }
 
@@ -144,7 +144,7 @@ export function findCapacityWindows(
     const lo = aStartDay - startDay;
     const hi = aEndDay - startDay;
     for (let i = lo; i <= hi; i++) {
-      allocHours[i] += alloc.hoursPerDay;
+      allocHours[i]! += alloc.hoursPerDay;
     }
   }