security: bound Zod inputs, add SSE per-user cap and tRPC body limit (#51, PR #59)

Closes #51 (ESLint rule + conventions doc remain as follow-up).

Co-authored-by: Hartmut Nörenberg <hn@hartmut-noerenberg.com>
Co-committed-by: Hartmut Nörenberg <hn@hartmut-noerenberg.com>

apps/web/src/app/api/reports/allocations/route.ts

@@ -1,6 +1,7 @@
 import { renderToBuffer } from "@react-pdf/renderer";
 import { createElement } from "react";
 import { NextResponse } from "next/server";
+import { z } from "zod";
 import { buildSplitAllocationReadModel } from "@capakraken/application";
 import { anonymizeResource, getAnonymizationDirectory } from "@capakraken/api";
 import { prisma } from "@capakraken/db";
@@ -11,6 +12,17 @@ import { createWorkbookArrayBuffer } from "~/lib/workbook-export.js";
 
 const ALLOWED_ROLES = new Set(["ADMIN", "MANAGER", "CONTROLLER"]);
 
+// Reject fantasy dates from clients — years outside [2000, 2100] are almost
+// certainly malformed input and would generate nonsensical SQL range scans.
+const DATE_MIN = new Date("2000-01-01T00:00:00.000Z");
+const DATE_MAX = new Date("2100-01-01T00:00:00.000Z");
+
+const queryParamsSchema = z.object({
+  startDate: z.coerce.date().min(DATE_MIN).max(DATE_MAX).optional(),
+  endDate: z.coerce.date().min(DATE_MIN).max(DATE_MAX).optional(),
+  format: z.enum(["pdf", "xlsx"]).default("pdf"),
+});
+
 export async function GET(request: Request) {
   const session = await auth();
   if (!session?.user) {
@@ -23,9 +35,20 @@ export async function GET(request: Request) {
   }
 
   const { searchParams } = new URL(request.url);
-  const startDate = searchParams.get("startDate") ? new Date(searchParams.get("startDate")!) : new Date();
-  const endDate = searchParams.get("endDate") ? new Date(searchParams.get("endDate")!) : new Date(Date.now() + 90 * 24 * 60 * 60 * 1000);
-  const format = searchParams.get("format") ?? "pdf";
+  const parsed = queryParamsSchema.safeParse({
+    startDate: searchParams.get("startDate") ?? undefined,
+    endDate: searchParams.get("endDate") ?? undefined,
+    format: searchParams.get("format") ?? undefined,
+  });
+  if (!parsed.success) {
+    return new NextResponse("Invalid query parameters", { status: 400 });
+  }
+  const startDate = parsed.data.startDate ?? new Date();
+  const endDate = parsed.data.endDate ?? new Date(Date.now() + 90 * 24 * 60 * 60 * 1000);
+  if (endDate < startDate) {
+    return new NextResponse("endDate must be >= startDate", { status: 400 });
+  }
+  const format = parsed.data.format;
 
   const [demandRequirements, assignments] = await Promise.all([
     prisma.demandRequirement.findMany({
@@ -62,21 +85,25 @@ export async function GET(request: Request) {
   const assignmentRows = allocationView.assignments.slice(0, 500);
   const directory = await getAnonymizationDirectory(prisma);
 
-  const rows = assignmentRows.map((a: AllocationLike & {
-    resource?: { id: string; displayName?: string | null } | null;
-    project?: { shortCode: string; name: string } | null;
-  }) => {
-    const resource = a.resource ? anonymizeResource(a.resource, directory) : null;
-    return {
-      resourceName: resource?.displayName ?? "Unknown",
-      projectName: a.project ? `${a.project.shortCode} — ${a.project.name}` : "Unknown project",
-      role: a.role ?? "",
-      startDate: new Date(a.startDate).toLocaleDateString("en-GB"),
-      endDate: new Date(a.endDate).toLocaleDateString("en-GB"),
-      hoursPerDay: a.hoursPerDay,
-      dailyCostCents: a.dailyCostCents,
-    };
-  });
+  const rows = assignmentRows.map(
+    (
+      a: AllocationLike & {
+        resource?: { id: string; displayName?: string | null } | null;
+        project?: { shortCode: string; name: string } | null;
+      },
+    ) => {
+      const resource = a.resource ? anonymizeResource(a.resource, directory) : null;
+      return {
+        resourceName: resource?.displayName ?? "Unknown",
+        projectName: a.project ? `${a.project.shortCode} — ${a.project.name}` : "Unknown project",
+        role: a.role ?? "",
+        startDate: new Date(a.startDate).toLocaleDateString("en-GB"),
+        endDate: new Date(a.endDate).toLocaleDateString("en-GB"),
+        hoursPerDay: a.hoursPerDay,
+        dailyCostCents: a.dailyCostCents,
+      };
+    },
+  );
 
   const ts = Date.now();