Add paycheck tracking workflow for v1

src/app/paychecks/route.ts

@@ -0,0 +1,28 @@
+import { NextResponse } from "next/server";
+
+import { createPaycheck, listPaychecks } from "@/lib/paychecks";
+import { paycheckInputSchema } from "@/lib/validation";
+
+export async function GET() {
+  const paychecks = await listPaychecks();
+  return NextResponse.json({ paychecks });
+}
+
+export async function POST(request: Request) {
+  const payload = await request.json();
+  const parsed = paycheckInputSchema.safeParse(payload);
+
+  if (!parsed.success) {
+    return NextResponse.json(
+      { error: parsed.error.issues[0]?.message ?? "Invalid paycheck payload." },
+      { status: 400 },
+    );
+  }
+
+  const paycheck = await createPaycheck({
+    amountCents: parsed.data.amount,
+    payDate: parsed.data.payDate,
+  });
+
+  return NextResponse.json({ paycheck }, { status: 201 });
+}