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/api/src/router/scenario-procedure-support.ts

@@ -1,9 +1,5 @@
 import { PermissionKey } from "@capakraken/shared";
 import { z } from "zod";
-import {
-  parseScenarioBaselineResult,
-  parseScenarioSimulationResult,
-} from "../lib/scenario-schema.js";
 import type { TRPCContext } from "../trpc.js";
 import { requirePermission } from "../trpc.js";
 import { applyProjectScenario } from "./scenario-apply.js";
@@ -38,16 +34,14 @@ export async function getProjectScenarioBaseline(
   input: z.infer<typeof ScenarioProjectIdInputSchema>,
 ) {
   requirePermission(ctx, PermissionKey.VIEW_COSTS);
-  const result = await readProjectScenarioBaseline(ctx.db, input.projectId);
-  return parseScenarioBaselineResult(result);
+  return readProjectScenarioBaseline(ctx.db, input.projectId);
 }
 
 export async function simulateScenario(
   ctx: Pick<TRPCContext, "db">,
   input: z.infer<typeof ScenarioSimulationInputSchema>,
 ) {
-  const result = await simulateProjectScenario(ctx.db, input);
-  return parseScenarioSimulationResult(result);
+  return simulateProjectScenario(ctx.db, input);
 }
 
 export async function applyScenario(